Language pedagogies and late-life language learning proficiency

2.1 Language outcomes in LLLL

In one of the earliest investigations (Gruneberg and Pascoe 1996), 40 healthy older adult females (Mage = 70.45) participated in a single session in which they either learnt word pairs using either a so-called keyword method (i.e., a word is linked to an English similarly sounding word by means of an image) or by merely being presented with the word pairs. This vocabulary learning was done by listening to an audio tape consisting of 20 English words and their Spanish translation. Results showed that both receptive and productive recall were significantly better in the keyword method group when being lenient with rating (i.e., substantially correct showing some knowledge of what the Spanish should be; the so-called soft criterion). When being less lenient in rating correctness of responses (i.e., almost correct, but not strictly phonetically correct for the middle criterion and totally phonetically correct for the hard criterion) there were no differences between the groups. Additionally, it needs to be pointed out that listening to 20 word pairs in a single session is not reminiscent of an actual language course.

Other studies, too, have focused on very specific language outcomes, for instance on question formation. In Mackay and colleagues’ (2012]) study, nine older Spanish L1 speakers (Mage = 72) met individually with a native speaker on a weekly basis for five weeks. This included testing sessions as well meaning that there were three language sessions in the study during which participants and native speakers used communicative tasks to elicit question forms. The duration of each training session is not included in the study. Results showed that question formation in participants improved after the sessions but only two out of nine adults managed to sustain this improvement. Similarly, older adults have been shown to frequently pose questions in the language classroom, but that a large portion of these questions were unrelated to the progressivity of the lesson. Instead, they asked “wonderment questions”: questions on something they wonder about (van der Ploeg et al. 2022).

In one of the only studies to date that comprise a longer time course than a few sessions, the time course of improvement could be more closely monitored. In Pfenninger and Polz’s (2018) study, 12 German-speaking older monolinguals and bilinguals (6 German/Slovenian sequential bilinguals, Mage = 84.33; 6 German monolinguals Mage = 68.20) were enrolled in a four-week English course. Although participants did significantly better on overall proficiency, no significant improvements were observed on receptive tasks. Interestingly, the bilinguals did not outperform the monolinguals. Taking an even longer language instruction perspective, Kliesch and Pfenninger (2021) followed 28 German older adults (Mage = 68.5) learning Spanish for 30–32 weeks in small groups. Instruction comprised both in-person classroom instruction and Duolingo practice at home. The authors found that the increase in AL mainly occurred during the initial 10–20 week interval of learning.

Finally, some studies have investigated factors to influence AL learning in older-adulthood; the similarity of known languages to English, L1 skills, and English language exposure predicted English skills in older adults (N = 19; M = 72.92) (Blumenfeld et al. 2017). This is corroborated by Kliesch and colleagues (2018]), who found higher L1 verbal fluency to be related to faster language learning rates.

The scant evidence to date points in the direction of the possibility of successful language learning in older adulthood. Although older adults in comparison studies have in general been found to be slower in learning a new language than their young adult counterparts (cf. Marcotte and Ansaldo 2014), the learning attested is promising and fits in well with self-fulfilment and self-achievement that is said to characterise the third age (see above).

But these studies do collectively render the question what can be done to promote language learning success in late life. Other than the study by Gruneberg and Pascoe (1996), the studies to date have not investigated different language teaching pedagogies. Building on applied linguistics studies in younger learners, one of the most fiercely debated topics is the effectiveness of more explicit versus more implicit language instruction methods (cf. Andringa and Rebuschat 2015). To date, this has never been applied to an older adult context. This study is the first to exploratively do so in a small sample of older adults. The main objective in doing so is to shed light on the optimal language learning trajectory for an emergent but substantial group of language learners: older adults. As a second aim, the study outcome may reciprocally aid theorising in the realm of applied linguistics. To do that, it is pivotal to present the state-of-the-art of applied linguistic investigations into implicit versus explicit language teaching pedagogies.

2.2 Implicit/explicit language teaching pedagogies

At its core, implicit and explicit language instructional methods differ in the metalinguistic input learners do or do not receive (Ellis 1994; Norris and Ortega 2000). To further complement this distinction are focus on form (FoF), focus on forms (FoFs) and focus on meaning (FoM; Long 1991). On a continuum these methods range from FoFs, which is mostly described as traditional and explicit grammar-based language teaching where meaningful interaction is largely absent, to FoM which tends to exclusively focus on communicative meaning (Long and Robinson 1998) and which is often equated with implicit language instruction: learners are expected to learn the language based on natural and abundant exposure and input. In between FoFs and FoM is FoF, where a focus on conveying a message is typically prioritised but the teacher also pays explicit attention to the form of the message.

Over the years there have been many studies investigating the effectiveness of these different language teaching methods. However, a consensus on which method is optimal is hard to reach (Andringa and Rebuschat 2015). The meta-analyses by Norris and Ortega (2000), Spada and Tomita (2010), and Goo and colleagues (2015]) seem to point in the direction of a clear advantage of explicit language instruction. But the studies that formed the basis for their syntheses, however, have been criticised on three aspects: (1) one specific grammatical structure is targeted (Rousse-Malpat and Verspoor 2012), (2) training is short (DeKeyser 2013), and, (3) task procedures and test circumstances favour explicit knowledge (Andringa and Rebuschat 2015). Indeed, a more recent meta-analysis comparing implicit and explicit teaching approaches showed that outcome measures were significant moderators in the effects of implicit and explicit instruction: in spontaneous AL use, implicit instruction showed stronger effects (Kang et al. 2019), whereas previous meta-studies (Norris and Ortega 2000; Spada and Tomita 2010) mainly incorporated controlled outcome measures that relied on metalinguistic knowledge.

Partly to address the critique of a short training, several studies have carried out longitudinal classroom-based intervention studies on the difference between implicit and explicit language instruction (Gombert 2023; Piggott 2019; Rousse-Malpat and Verspoor 2012). Results showed that on usage-based holistic measures related to speaking and writing fluency, the implicitly taught group tended to outperform their explicitly taught peers. Whereas the explicit groups initially tended to outperform their implicitly taught peers on complexity, accuracy and fluency (CAF) measures, this difference disappeared with time. This state-of-the art of studies in this domain has so far relied solely on young (predominantly secondary school) learners.

Importantly, many studies have referred to the difference in terms of mostly implicit and mostly explicit conditions. Indeed, implicit versus explicit language instruction is a continuum and fully implicit or explicit instruction does not exist (Van den Branden 2016; Verspoor et al. 2015).

2.3 Implicit/explicit language teaching pedagogies in LLLL

Translating these findings on explicit versus implicit instruction to learners in the older adult life stage is impossible due to effective methods of late life language learning and teaching being greatly under-researched. Tentative evidence comparing different age groups of language learners have pointed to younger adults benefiting more from explicit grammar instruction than older adults do. This was attested in two studies that both targeted the learning of Latin. Cox and Sanz (2015) taught basic Latin morphosyntax to younger (N = 10; 19–27) and older (N = 11; 60+) English/Spanish bilinguals. In three sessions (duration unclear) over four weeks that participants completed, amongst other things, explicit grammar instruction and practice that provided them with correct/incorrect feedback without an explanation (i.e., no explicit instruction). Younger participants benefited more from explicit instruction, which the authors ascribe to the task’s memory demands but may also be due to the younger participants being much more used to this type of instructional setting. Significant differences previously observed between the age groups disappeared two weeks after the grammar lesson and practice session. The authors ascribe this to the fact that older adults’ language developmental process operated over a longer time compared to younger learners. Although Lenet and colleagues (2011]) also investigated Latin (semantic function assignment), they did incorporate an explicit and less explicit condition. Younger (N = 20; Mage = 18.7) and older (N = 20; Mage = 72.3) adults were provided with feedback that either just told them their answer was incorrect (less explicit), or told them why their answer was incorrect (explicit). Similar to Cox and Sanz’s (2015) study, the duration of the sessions is not mentioned in the article either. Results showed that the younger group did better in the explicit condition whereas the older adults did better in the less explicit condition.

Finally, Midford and Kirsner (2005) studied older (N = 22; Mage = 65.9) and younger (N = 22; Mage = 20.6) adults on an artificial grammar-learning paradigm. Grammar instruction varied in complexity and use of rules, leading to four conditions. After this training phase, with an unknown duration, participants were asked to complete a grammar-judgement task. In the simple-grammar condition with rules, the younger group performed better than the older group; however, in the complex-grammar condition without rules, these differences disappeared. The authors conclude that less explicit grammar instruction works better for older adults.

Collectively, these studies show a tendency for implicit instruction being more beneficial for older adults. At the same time, however, it needs to be pointed out that this conclusion is not without problems: groups were small, but most importantly, instruction and training sessions were very brief (and the precise duration was unclear) and did not resemble language course set-ups since they took place in a lab setting rather than classroom environment, limiting the generalisability of the studies’ results. Similarly, the language of instruction was either an artificial language or Latin. Finally, but crucially, the studies differentiated between no versus explicit instruction, albeit that explicit language instruction was operationalised differently (grammar explanation vs. feedback), but at no point was a more explicit versus more implicit learning conditions introduced. Lacking are studies building on tentative work (detailed in 2.1) that older adults can learn a new language but looking specifically at the optimal conditions to do this , in a naturalistic classroom setting where older adults are learning a new language over a longer period of time (DeKeyser 2013; Lambert and Kormos 2014; Larsen-Freeman 2015; Rebuschat 2015).

2.4 The present study

Following the caveat in earlier work, we designed a three-month English as an additional language (AL) course for older adults, specifically comparing more implicit versus explicit language instruction in an actual late-life language classroom setting. We aim to answer the following research questions:

1. Does older adults’ overall AL proficiency improve after a three-month language course and to what extent is this dependent on language teaching pedagogy?

2. To which extent do implicit versus explicit language teaching pedagogies differ in CAF and holistic rating scores of spoken assignments?

Based on earlier work, we hypothesise that older adults’ overall AL proficiency does show improvements after three months of language instruction (cf. Kliesch et al. 2021), but that the groups show differences in several areas of development. As there is more room to practise speaking in the implicit grammar condition (see below for details), we expect this group to show more substantial improvements on speaking tasks. Regarding the second research question, if the findings of our study resemble those attested in studies on younger learners, we hypothesise that explicitly taught older adults outperform implicitly taught older adults on holistic grammar and accuracy ratings. The implicitly instructed group, however, are expected to do better on measures of fluency (Piggott 2019; Rousse-Malpat and Verspoor 2012).

3.1 Participants

Sixteen Dutch older adults (M = 71;9, SD = 6;3, 13 female) participated in our longitudinal study till the end. Educational levels varied from secondary school to university degrees. All participants were retired at the time of testing; former professions included police officer, secretary, teacher, and business owner. Based on self-reports, the average number of languages/dialects spoken per participant was 4 (this included languages learnt at school or other places and regional languages/dialects). An additional 14 participants initially started with the English course but dropped out due to health issues (N = 6), difficulty with online technology (N = 4), perceived difficulty of the course (N = 3), and not liking the teaching pedagogy to which they were assigned (N = 1; see below for further details). A number of inclusion criteria were in place. Based on Nijmeijer and colleagues (2021]), older adults had to: (a) be aged 65–80, (b) have a maximal B1 English proficiency level (CEFR), and (c) have no cognitive problems (based on the Montreal Cognitive Assessment [MoCA]; Nasreddine et al. 2005). Participant recruitment took place via Facebook advertisements and a message in newsletters of older adult organisations in the Netherlands. The study was approved by the Research Ethics Committee at the University of X (61890455).

3.2 Study design

Our study followed a pre-test, post-test, retention test design where the retention test was administered three months after the post-test. Between the pre-test and post-test, participants followed a three-month English course that included weekly group lessons, and homework with a daily diary. The full experimental design and timeline of the study is detailed in Figure 1.

Figure 1:

Study design with test moments and design of the language course.

3.3 Course design and language learning procedure

Participants took part in a three-month English course specifically developed for, and targeted towards, older adults. This course consisted of twelve two-hour lessons (see Appendix A for topics and features for each lesson). Due to the COVID-19 pandemic, the course was held online. In order to investigate the implicit/explicit dichotomy, the course was offered in two versions to which participants were randomly assigned: one with more explicit language instruction (N = 8), operationalised mainly as explicit grammar instruction, and the other with mostly implicit instruction (N = 8), devoid of explicit grammar rule instruction. In line with previous research (Van den Branden 2016; Verspoor et al. 2015), in our course design we adhere to the premise that ‘purely’ implicit or explicit language teaching is difficult to accomplish (Long 1991). The explicit condition was not fully explicit because grammar was not explained in absence of any other linguistic input. Additionally, in the implicit condition, explicit attention was sometimes paid to word meaning or pronunciation.

Both classroom materials and homework assignments were adapted to fit either implicit or explicit instruction. In the explicit condition, grammatical constructs were explicitly explained (i.e., when to use a tense and how to form it), whereas the implicit condition included example sentences and exercises with the target structure, so essentially was input only. Figure 2 provides an example of the different exercises in the conditions when it comes to grammar explanations.

Figure 2:

Explicit (left) and implicit (right) explanation of present simple.

Other than the explicitness of grammar instruction, the two courses were identical. This meant that exercises and topics were also kept as similar as possible, except for the explicitness of the grammatical structure. In another example in Figure 3, the explicit condition is prompted to use the present simple, whereas the implicit condition is provided with more example sentences without changing the essence of the exercise on describing habits.

Figure 3:

Explicit (left) and implicit (right) exercise on describing habits.

Two rounds of pilots were carried out before data collection commenced (respectively N = 2, M = 77;9, SD = 3;6, 2 male; and N = 8, M = 70;9, SD = 4;3, 6 male) on both implicit and explicit conditions (explicit N = 6; implicit N = 4). The main purpose of the pilots was to ascertain feasibility of the testing sessions (including materials) and the course itself (i.e., whether the instructional conditions could be maintained as desired). As a result of the pilots, minor alterations were made which mainly pertained to homework and online formats, such as switching to Google Docs (instead of Google Classroom).

Both during the pilot rounds and the actual data collection, teachers were instructed on what to say in case participants in the implicit group asked explicit grammar questions. These answers followed along the lines of ‘this is not important right now; we are focusing on other things now’. However, none of the participants in the implicit condition ever asked such questions.

3.4 Language tests

During all three testing moments (pre, post and retention test), several language proficiency tests were administered via Google Meet, comprising both productive and receptive language tasks.

3.5 Analysis

Linear mixed model analyses were run to analyse the data using the lme4 package (Bates et al. 2015) in R (R Core Team 2021). Language test scores were included as dependent variables, test moment (pre-, post-, and retention test or week/day) and condition (implicit and explicit) were included as independent variables with an interaction. Participant, finally, was included as random effect, as older adults have been shown to show substantial individual variation (Christensen 2001; Grotek 2018). Additionally, in the homework models, task was also included as a random effect as the topics of the tasks differed and this may have influenced the results. Conditional R2 was computed using the mgcv package (Wood 2017) and the scores for all language tests were centred around zero, based on the pre-test scores. Graphs were created using ggplot2 (Wickham 2016). Model output for all models can be found in Appendix C.

4.1 Global proficiency measures

4.1.1 Speaking

In the overall IELTS rating of the speaking tasks, we found a significant effect between time and speaking scores (conditional R2 = 0.78). Our model showed a significant main effect for retention test (b = 0.52, SE = 0.17, t = 3.04, p < 0.01, CI[0.18, 0.87]), which means that, regardless of condition, older adults spoke better English overall as part of the retention test than in the pre-test. Subsetting showed that there was no significant difference between post-test and retention test (p = 0.071). Figure 4 shows both the explicitly and implicitly taught groups’ performance on the speaking task.

Figure 4:

IELTS speaking scores per condition over time (left to right: overall, lexical resources, grammar, pronunciation). Note: scores are centred around zero.

As a next step, we investigated the IELTS ratings in more detail and found a significant effect between time and IELTS speaking – lexical resources scores (conditional R2 = 0.72). Our model showed a significant main effect for retention test (b = 0.50, SE = 0.23, t = 2.22, p < 0.05, CI[0.04, 0.96]), so – similar to overall IELTS speaking scores – older adults, regardless of condition, did better on the retention test on lexical components in speaking than in the pre-test. Subsetting showed that there was no significant difference between post-test and retention test (p = 0.68). In Figure 4 participants’ lexical speaking scores are visualised, split per explicit and implicit teaching condition.

For IELTS speaking – grammar scores in interaction with time we also found a significant effect (conditional R2 = 0.81). Our model showed a significant main effect for retention test (b = 0.44, SE = 0.21, t = 2.09, p < 0.05, CI[0.01, 0.86]), where, again, older adults, regardless of condition, did better on the retention test on grammar components in speaking than in the pre-test. Subsetting showed that there was no significant difference between post-test and retention test (p = 0.109). See Figure 4 for a visualisation.

Finally, for IELTS speaking – pronunciation, the trend was the same as for the other three IELTS test components: we found a significant effect of time (conditional R2 = 0.76). Our model showed a significant main effect for retention test (b = 0.59, SE = 0.21, t = 2.82, p < 0.01, CI[0.17, 1.02]): regardless of condition, older adults’ English pronunciation performance was significantly better on the retention test compared to the pre-test. Subsetting showed that in the retention test, participants did significantly better than in the post-test (p < 0.01). Below, Figure 4 shows the performance of both groups.

Although this has to be treated with caution, Figure 4 does visualise different trends in both conditions (though at no point resulting in significant differences). Whereas the implicit group mainly stays stable in their development before and after the course, the explicit group shows an increase in their scores. This increase is sustained in the retention test which, in all four cases, shows even higher scores than the post-test.

For the CEFR rating of the speaking task we found significant effects between time and speaking scores (conditional R2 = 0.68). Our model showed a significant main effect for post-test and retention test (b = 0.32, SE = 0.12, t = 2.71, p = 0.01, CI[0.08, 0.56]; b = 0.46, SE = 0.12, t = 3.93, p < 0.001, CI[0.22, 0.70]): older adults, regardless of their assigned teaching method condition, performed better in both post-test and retention test compared to pre-test. No significant difference in performance was found between post-test and retention test (p = 0.23).

As opposed to IELTS overall, as well as its lexical, grammar and pronunciation components and for the CEFR rating on the basis of the IELTS speaking test, IELTS fluency ratings did not reveal any improvement over time nor were any effects of condition found.

4.1.2 Vocabulary

Turning to receptive vocabulary, we found a significant effect of time for English vocabulary (i.e., performance on the Peabody picture vocabulary test) (conditional R2 = 0.73). Our model showed a significant main effect for retention test (b = 12.75, SE = 5.42, t = 2.35, p < 0.05, CI[1.79, 23.71]; b = 24.62, SE = 5.42, t = 4.54, p < 0.001, CI[13.67, 35.58]), pointing to older adults, regardless of condition, to show the best receptive command of English words at the time of the retention test compared to their performance on the pre-test. Subsetting showed that participants did better on the retention task than on the post-test (p < 0.05). In Figure 5 both groups’ performance is plotted.

Figure 5:

Peabody scores per condition over time. Note: scores are centred around zero.

4.1.4 Verbal fluency

For English verbal letter fluency, we found a significant effect between time and scores (conditional R2 = 0.66). However, our model only showed a significant main effect for the retention test (b = 7.75, SE = 2.44, t = 3.17, p < 0.01, CI[2.82, 12.68]). Regardless of condition, and similar to receptive English vocabulary, older adults named more correct words in the retention test. No significant differences were found between groups between post-test and retention test (p = 0.68). Figure 6 shows participants’ performance.

Figure 6:

English verbal fluency scores per condition over time. Note: scores are centred around zero.

4.2 CAF versus holistic scores of spoken homework samples

4.2.1 CAF

For complexity, both lexical complexity (as measured by the MATTR) and syntactic complexity (as measured by coordinate phrases per T-unit), no significant effects were found across time or between the conditions.

For accuracy, we found no significant effects for lexical errors. For structural errors, however, we found a significant main effect (conditional R2 = 0.41). Our model showed a significant main effect of condition (b = 0.02, SE = 0.01, t = 2.77, p < 0.01, CI[0.01, 0.04]) and an interaction between time and condition (b = −0.00, SE = 0.001, t = −2.92, p < 0.01, CI[−0.00, −0.00]). More specifically, our results indicate that, even though the implicitly taught group made more structural errors than the explicitly taught group overall, compared to the explicit group the implicit group showed a significant decrease in structural errors over time (see Figure 7).

Figure 7:

Structural errors corrected for length over time per condition including SEs.

For fluency, only one significant main effect was found for the various fluency indicators under investigation: for mean number of words per minute, number of silent pauses per minute, mean length of silent pauses, number of filled pauses per minute, and number of repairs/repetitions per minute no main effect was found. For speech rate (conditional R2 = 0.72), the model showed a significant main effect of time (b = 0.03, SE = 0.01, t = 2.78, p < 0.01, CI[0.01, 0.05]). This indicates that older adults’ overall speech rate improved over the course regardless of condition. Indeed, we did not find any significant main effect of condition (p = 0.21) or interaction between condition and time (p = 0.97). See Figure 8 for a visualisation of these results.

Figure 8:

Speech rate over time per condition including SEs.

4.2.2 Holistic scores

For holistic grammar scores we found a significant effect (conditional R2 = 0.44). The model showed a significant main effect between time and grammar scores (b = 0.04, SE = 0.02, t = 2.29, p < 0.05, CI[0.01, 0.08]), meaning that, regardless of condition, our participants’ holistic grammar scores improved over the timespan of the course. The model did not show any significant main effect of condition (p = 0.62) or interaction between condition and time (p = 0.58). This is visualised in Figure 9.

Figure 9:

Holistic grammar scores over time per condition including SEs.

For vocabulary, fluency, and functional adequacy, no significant effects were found.

5.1 Limitations

There are several limitations to our study that we wish to touch upon. First of all, our exploratory study’s sample size was small. This means that the statistical outcomes need to be interpreted with caution. In addition, we did not control for participants’ English starting level as there was not enough power in our models to do so. However, we urge future studies to include this variable in their models. Secondly, staying on the topic of statistics, our homework data consisted of different tasks. Even though we controlled for this potential task effect in our statistical models, future research might want to incorporate a single measure over time. This, of course, comes with new challenges, such as fatigue and potential drop-out, something that is especially present in older-adults. Another factor that needs to be taken into account is that three older adults had to be removed from the analysis of homework data as they had read their spoken assignments out loud. For these participants it was very clear that they read their assignments out loud (i.e., turning papers can be heard in the recordings), but there might of course be more older adults who did this, influencing the results. A third limitation is the fact that both testing sessions and actual teaching and homework had to be organised in an online setting. Although our study has shown that such a set-up is feasible for older adults, it also might have influenced the results as listening tasks in such a set-up are much harder to carry out and technical issues with, for example, internet connections will always be present. Finally, there are two limitations we already touched upon when discussing the results: language training might have been too short to demonstrate differences between the two conditions, and the implicit and explicit condition might have been too similar.

5.2 Conclusions and implications

Our small-scale longitudinal dense data study showed that it is possible for older adults to develop their AL proficiency, even during a relatively short course of three-months. Moreover, such language proficiency gains can even be attained in an online language course. Regarding implicit and explicit grammar instruction, we found no noteworthy differences: the implicit condition showed more structural errors yet also significantly went down in these errors during the course.

From an SLA-theory perspective this means that previous research into implicit and explicit grammar instruction has been biased towards younger learners and that it remains to be seen whether the results regarding younger learners hold true once older language learners are incorporated into research designs.

Practically speaking, seeing that there were no substantial differences between the two teaching pedagogies, and the fact that participant attrition was quite high in this study, it might be best to adopt a teaching pedagogy that meets older adults’ language learning needs best. A needs analysis revealed older adults to want explicit explanation of grammatical constructs (van der Ploeg et al. submitted), and one of our participants dropped out of the course due to a lack of explicit grammar instruction. Hence, a communicative-focused teaching pedagogy that does include some explicit grammar instruction might be most suitable for older adults.

Finally, our study showed the late-life language learner (as far as one can talk about ‘the’ late-life language learner) to be very invested in the course. The fact that multiple participants had to be excluded from part of the analysis due to them reading assignments out loud shows that they want to do a good job and that they put a lot of energy and effort into their language learning. By doing so, they show agency over their language learning process.