Volume 47, Issue 3-4

The main purpose of this paper is to show that the observation which is the starting point for almost all attempts at explaining intrinsic fundamental frequency (intrinsic F₀) in vowels, i.e. that it is correlated with vowel height (interpreted as tongue height), does not hold if short lax vowels are included, since they have a considerably lower tongue height but practically the same F₀ as their corresponding tense counterparts. Section 1 contains a discussion of some explanations of intrinsic F₀ and vowel height and a short exposition of its connection with other vowel features. Section 2 gives a survey of the properties of tense and lax vowels based on data from the phonetic literature. Section 3 reports on an investigation of German tense and lax front unrounded vowels, including duration, tongue height, jaw opening, vertical lip opening, formant frequencies, and F₀. Section 4 contains a discussion of various possible explanations of the results.

The relationship between the electromyographic (EMG) activity from the pars obliqua of the cricothyroid (CT) muscle (recorded with bipolar hooked-wire electrodes) and the intrinsic fundamental frequency (IF₀) in high and low vowels in Danish was investigated. The test material, which consisted of 306 randomized natural words of the type CV(:)l3, imbedded in carrier sentences, was recorded by 4 native speakers of Danish. The following vowel pairs were compared: [‘i-’a, ‘i :-’æ:, ‘u :-’æ:] and [‘i :-’a]. The results, which are based on visual inspection of average EMG and fundamental frequency (F₀) curves, show a positive correlation between the CT activity and IF₀, more specifically that the CT activity rise related to the high vowels starts earlier and in most cases more steeply than the CT activity related to the low vowels. However, a drop in F₀ at the beginning of the low vowels cannot be accounted for by CT activity. This F₀ drop is believed to be the result of either tongue retraction during the articulation or influence from the preceding consonant. The following conclusion is drawn: The CT muscle is a major factor in controlling IF₀ in stressed high and low vowels in Danish.

Three experiments examined the conditions under which the speaking rate of a context sentence affects vowel identification. In these experiments, listeners identified the vowel in synthetic /b/-vowel-/t/ syllables that varied systematically in the duration (temporal), the formant frequencies (spectral), or both the duration and formant frequencies (temporal-spectral) of the steady-state portion of the syllable. These syllables were embedded in two synthetic sentence frames, one with the temporal characteristics of a natural fast sentence and one with those of a slow sentence. For two vowel distinctions that are specified in natural speech by both temporal and spectral characteristics, /I/-/i/ and /ε/-/æ/, listeners adjusted their identification of the vowels according to the sentence rate in all three conditions. Although there was a trend for the rate effect to be reduced in the temporal-spectral condition, the influence of sentential rate was never eliminated. By contrast, for a vowel distinction that is naturally specified primarily by spectral characteristics, /ε/-/ι/, there was no effect of sentence rate in any of the conditions. We conclude that when vowels are differentiated in natural speech by both temporal and spectral information, listeners obligatorily use the duration of the vowel to identify it and do so in relation to the rate of the sentence in which the vowel occurs.

Amplitude measurements of 32 whispered tokens of /p/ and /b/ produced in four vowel contexts revealed that whispered /b/ tended to have a steeper rise slope relative to the following vowel than did /p/. In a perceptual experiment, short (60-ms) whispered stop + vowel utterances were played to 8 listeners. Their identification scores were significantly above chance, but lower than what might be expected for stop + vowel stimuli produced with normal voicing. The pattern of identifications showed no relationship to the measured rise time differences.

Acoustic analysis of six different regional variants of Standard Danish, two forms of Swedish and two of German divides the ten into two major categories: those that signal sentence intonation function by local cues and those that do it by global means. The purely global types are also those that have no default sentence accents, and which signal focus by reduction of the surroundings rather than by boosting of the focussed element (a focal accent proper). A specific final completion cue is restricted to the local intonation types and is there an entity separate from that which cues prosodic terminal or nonterminal status. The implication for models of intonation is discussed.

In this report we consider the possibility that speech analysis techniques may be used to determine whether an individual was intoxicated at the time that a voice recording was made, and discuss an analysis of the speech produced by the captain of the Exxon Valdez recorded at several points around the time of the accident at Prince William Sound, Alaska. A review of previous research on the effects of alcohol and other effects on speech production suggests that it may be possible to attribute a certain, unique pattern of changes in speech to the influence of alcohol. However, the rate of occurrence of this pattern or the reliability of a decision based on observations such as these is not known. Acoustic-phonetic analysis of a small number of tokens of Captain Hazelwood’s speech recorded before, during and after the accident revealed a number of changes in speech behavior which are similar to the pattern of changes observed in previous laboratory-based research on the effects of alcohol on speech production. We conclude with a discussion of the limitations in making inferences concerning the state of the speaker upon the basis of phonetic data and then discuss several possible explanations of the pattern of change found in the recordings of Captain Hazelwood.

The syllable repetitions of 6 child and 6 adult stutterers were investigated to establish whether dysfluent speech had a higher noise-to-signal ratio than fluent speech and whether this differed between children and adults. As predicted, the stuttered speech had a higher noise level for both age groups. During dysfluencies, the level of the noise components in the children’s speech was higher than in the adults.