An ambiguous segment is a phone that may or may not function as the nucleus of a syllable.
An ambiguous segment may also be described as functioning as either a vowel or a consonant, depending on its position in a syllable.
Here is a table that gives a description of some kinds of ambiguous segments with examples of each:
(Close vowels in certain environments)
Close vowels (for example, [i] and [w]) are not usually considered ambiguous in the following environments:
- Between two consonants
- Between a consonant and a word boundary
- When they are stressed
- When they bear tone