Aspiration

We will turn our attention to rules of pronunciation in English, starting with aspiration, to see what some of these regularities are. In the first set of words below, the phonemes /p, t, k/ are aspirated whereas they are not aspirated in the second set of words.

The selection of an aspirated versus an unaspirated voiceless stop is determined by the context in which the stop appears. Aspirated stops appear at the beginning of a word, whereas unaspirated stops appear after [s]; aspirated stops appear before a vowel or a sonorant consonant, whereas unaspirated stops appear at the end of a word. This collection of contexts can be expressed succinctly by referring to the position of the consonant in the syllable: aspirated stops appear at the beginning of the syllable and unaspirated stops appear elsewhere.

We assume that the voiceless stops are basically unaspirated in English, and explain where aspirated segments appear by having a rule that assigns aspiration to voiceless stops, only when the stop is at the beginning of the syllable: the rule can be stated as “voiceless stops become aspirated at the beginning of a syllable.” We don’t need a second special rule to derive unaspirated stops in other environments, because that follows directly from our assumption that the basic or underlying form of the voiceless stops in English is unaspirated, and they will therefore be pronounced as such unless they are specifically changed by a rule. We investigate the idea of underlying representations in greater detail in chapter 4.

Actually, the issue of aspiration in English is a bit more complex. Notice that in the following words, [p], [t], and [k] in the middle of the word are not aspirated, even though the consonant is between vowels or syllabic sonorants – between syllable peaks – and therefore is presumably at the beginning of a syllable.

Compare these words with seemingly analogous words where there is aspiration on the stop between vowels, such as [əˈt h æk] attack, [əˈkh juwmjəˌlejt] accumulate, [ˈlejˌt h ɛks] latex, [əˈph ɛndɪks] appendix. The important difference in these words is the location of stress. In all of the words in (4), where a voiceless consonant is not aspirated in syllable-initial position, the consonant is followed by an unstressed vowel. In other words, these data force us to refine our statement of the rule for assignment of aspiration, to be “voiceless stops become aspirated at the beginning of a stressed syllable.” The next chapter introduces the details for formalizing rules, but for the present we can express that rule as follows.

This statement introduces the method of writing rules, which will be used in the book. Rules generally take the form “A!B/C_D,” where A, C, D are variables that stand for single segments like [l] or [d] or phonetic classes such as “voiceless stop,” and B describes the nature of the change, some phonetic parameter such as “voiceless” or “nasal.” The conditioning context might involve only a preceding element in which case “D” would be missing, it might involve only a following element in which case “C” would be missing, or the applicability of the rule might depend on both what precedes and what follows. The arrow means “becomes,” the slash means “in the environment” where the context is what follows the slash. The notation “[ˈσ” means “beginning of a stressed syllable,” thus “voiceless stops become aspirated when they are preceded by the beginning of a stressed syllable.” The final chapter of the book introduces syllables in more detail.

Alternations involving aspiration. The dependence of aspiration on the location of stress leads to discovering further evidence for an aspiration rule. Certain word-formation processes in English change the location of stress, for example in atom the stress is on the first syllable of the root and in the related adjective atomic the stress is on the second syllable. The pairs of words in (6) further illustrate the property of stress shifting, where the verbs on the left have stress on the second syllable of the root but the nouns derived from these verbs on the right have no stress on the second syllable.

As predicted by our rule for aspiration, the phonetic presence or absence of aspiration on the medial stop of the root may alternate within a given root, according to where the stress appears in the root.

Another set of examples involves the word-formation process adding -ee to a verb, to form a noun referring to the direct object of the action. That suffix must be stressed, unlike the subject-nominalization suffix -er.

Again, as our rule predicts, when the stress shifts to the suffix vowel, the pronunciation of the preceding consonant changes to become aspirated.

Pronunciation of novel utterances. Not only does the existence of this aspiration rule explain why all voiceless stops are aspirated at the beginning of a stressed syllable in English words, it also explains facts of language behavior by English speakers outside the domain of pronouncing ordinary English words. First, when English speakers are faced with a new word which they have never heard before, for example one coming from a foreign language, voiceless consonants will be aspirated or unaspirated according to the general rule for the distribution of aspiration. The pronunciation of unfamiliar foreign place names provides one simple demonstration. The place names Stord (Norway) and Palma (Mozambique) will be pronounced by English speakers as [stɔɹd] and [ph almə], as predicted by the aspiration rule. The name Stavanger (Norway) may be pronounced many ways – [stəˈvæŋɹ̩], [ˈstævəndʒ ɹ̩], [stəˈvændʒ ɹ̩], [ˈstævəŋɹ̩], and so on, but consistently throughout this variation, the /t/ will remain unaspirated because of its position in the syllable. In the English pronunciation of Rapallo (Italy), stress could either be on the first syllable in [ˈɹæpəlow], with no aspiration because /p/ is at the beginning of an unstressed syllable, or on the second syllable as in [ɹəˈph alow] – again the choice of aspirated versus unaspirated consonant being determined by the rule of aspiration.

Second, when English speakers attempt to learn a language which does not have the same distribution of aspirated and unaspirated consonants as in English, they encounter difficulties in pronunciation that reflect the effect of the rule of aspiration. Hindi has both aspirated and unaspirated voiceless stops at the beginning of syllables, as well as after /s/. Words such as [ph al] ‘fruit’ and [stan] ‘breast’ are not difficult for English speakers to pronounce; accurate pronunciation of [pal] ‘want’ and [sth al] ‘place’ on the other hand are. This is due to the fact that the rule of aspiration from English interferes in the pronunciation of other languages.

Finally, even in native English words, unaspirated stops can show the effect of the aspiration rule in hyper-slow, syllable-by-syllable pronunciation. Notice that in the normal pronunciation of happy [ˈhæpij], only the first syllable is stressed and therefore [p] remains unaspirated. However, if this word is pronounced very slowly, drawing out each vowel, then both syllables become stressed, and as predicted the stop p is aspirated – [ˈhæ::]...[ˌph i::j]. All of these facts are explained by one simple hypothesis, that in English the occurrence of aspiration on stops derives from applying a rule.