The grouping of sound segments can be based on two types of criteria, the physical properties of segments (ie phonetic criteria) and the language-specific behaviour of segments (ie phonological criteria). The analyst can only hope that the result of these two types of categorization converge, that is, segments that sound similarly, also behave in a similar way. Let us see the grouping of British English vowels. For a first approach, we will examine three basic phonotactic environments, we will see which vowels can occur before a consonant, before a vowel, and at the end of the word. The following chart contains the result of this test.
We see that any vowel may occur in preconsonantal position (__C). This is not a surprising result, it is possibly true for vowels in most natural languages. With the exception of unstressed schwa (
Long monophthongs, schwa, and all diphthongs may occur word finally, but only diphthongs may occur before a vowel. Since diphthongs all end in an offglide, it seems that there is no hiatus»A hiatus is two adjacent vowels without a consonant between them. The word hiatus itself is an example, at least in many languages, perhaps not English:
The only unnatural group we have is the middle one containing the long monophthongs and a short monophthong, schwa. This set is often referred to as the R vowels, because if a word ends in one of these vowels and the next word begins with any vowel, an
By fine tuning the criteria we get more refined groupings. Let us add two new criteria. On the one hand, we examine stressed and unstressed syllables. Schwa is the only vowel that exclusively occurs in an unstressed syllable, we do not find it in a stressed syllable. In this way we can separate schwa from the rest of the R vowels, which are all long, while schwa is short.
On the other hand, we now make a difference between two types of preconsonantal position: some vowels may occur before a single consonant, but not before a consonant cluster, while other vowels are possible in both environments. It is only three R vowels,