Distribution of Phonemes
English, like all other languages, has its unique phonological rules regarding the distribution of phonemes. These rules are called phonotactics. Phonotactics describe permissible sequence of phonemes in a language; such as which phonemes can (or cannot) occur in certain positions in words and which can or cannot cluster (combine). For example, not all phonemes can occur in initial positions in words. The phoneme /ʒ/ heard in words like measure, leisure and mirage do not occur in initial position. That is, no English word begins with the phoneme /ʒ/. The same rule holds for the phoneme /ŋ/ which is heard in words like sing, tongue.
There are others which are not allowed to cluster (or combine) in certain positions. For instance, /ʧ/ heard in church, chair, beach cannot be followed immediately by another consonant phoneme. /ʧ/ can follow a consonant, but it cannot be followed by another consonant so it is always followed by a vowel phoneme. The same rule applies to /ð/ as in this, clothe, weather: it is never immediately followed by another consonant phoneme. Native English speakers learn these rules very early as children and so are able to distinguish native English words from foreign ones.
Stress, one of the main elements of English non-segmental (suprasegmental) phonology, is a key feature of English phonology and plays an important role in reading and spelling. It is one aspect of English phonology that is least discussed in literacy resources.
In my experience as a literacy instructor, I have come to understand that stress affects native English speakers and non-native English speakers in different ways. Native English speakers’ lack of understanding of stress is often revealed in their misspelling of unstressed syllables. On the other hand, non-native speakers’ lack of understanding of stress shows up in their pronunciation as they tend to pronounce all syllables, including unstressed syllables, with the same amount of force.
This is intended to give you an idea of the scope of English phonology by highlighting some of its important aspects.