PHONOLOGICAL RULES

It often happens in language that the phonetic environment before or after a sound influences how this sound is pronounced. The phonetic environment prompts a change from a sound's pronunciation in isolation. Non-native speakers of English can be rather sensitive to such deviations from the expected pronunciation. For example, I remember wondering and asking my teachers why English speakers thought that the sounds in cat and can or hat and ham were the same.

What happens here is that the [n] and [m], "color" the preceding vowel. Working out the articulatory descriptions of these two sounds you will realize that they have the property nasal in common: even though they have different places of articulation they are both nasals. Therefore we can generalize that the phonetic environment involving the natural class of nasals triggers the observed pronunciation change. In doing so, we lower our velum (the soft palate) in anticipation of the following nasal, for which it needs to be lowered so the air can escape through the nose. (Remember that nasals are characterized by complete stoppage of the airstream in the mouth and release of the air through the nose!?) The phonetic environment responsible for the pronunciation change therefore consists of all members of the natural class of nasals. Found that any time comes before a nasal, becomes itself nasalized. The rule of nasalization is therefore a phonological rule because it describes the systematic relationship between sounds, specifically here the relationship between a regular sound and a nasalized sound.

There are many phonological rules in a language, but we will only discuss a few from English. Phonological rules can be classified into four major kinds. They are assimilation, dissimilation, insertion and deletion. We will discuss four rules, each demonstrating one of these kinds. There are at least two reasons why this discussion is relevant for language teachers. One I gave above: language learners may notice (and trip over) the changes triggered by phonological rules. Another reason is that these pronunciation changes often account for pronunciation characteristics perceived as native-like. Understanding phonological rules provides the tools for teaching more native-like pronunciation, an goal important to many non-natives. Listen to sample 19 for samples of each rule.

Assimilation. Rules of this kind describe processes where a sound becomes more similar to a neighboring sound. Nasalization, described above, is an example of assimilation. When nasalization happens, a vowel right before a nasal consonant becomes more similar by obtaining a nasalized quality; in other words, it takes on the feature nasal. As the books states, assimilation is VERY common in languages.

Dissimilation. This type of rule refers to processes whereby two neighboring sounds become less similar. An example is the rule of fricative dissimilation. This rule always caught my interest because Germans, like speakers of many other languages, cannot easily pronounce the th sounds. In learning the ordinal numbers, the numbers fifth and sixth always presented a pronunciation challenge in this regard. It is difficult to pronounce two fricatives next to one another when one of them involves the th sound that does not exist in one's language. When I started living in the United States, I was very relieved to find out that such sound sequences appear to present challenges for many native speakers, too, and that they therefore make one of the two sounds more different from the other. As a result, fifth is pronounce as [fIft] and sixth as [sIkst]. The second fricative becomes a stop, which makes it more dissimilar and easier to pronounce. I wish my English teachers would have known about this rule and saved me some grief!

Insertion. In this kind of process a sound is added that is not present in slow pronunciation or spelling. For example, when we pronounce the word hamster at a regular speed, most of us will say and hear hampster with a p. This can be confusing when teaching spelling, especially to non-native speakers who don't have a history of reading and hearing English words and their spelling. I recall being puzzled by the pronunciation and spelling of the word month. I was hearing (and wanted to spell) mon-t-th with an additional t between the n and the th.

Deletion. Finally, there are types of pronunciation processes where sounds are left off. For example, when pronouncing the word police, the word often sounds like pleace and may be confused with please if one is not used to hearing voiced s, as was the case for me (we don't use voiced [z] in my Southern German dialect). This unstressed vowel deletion is fairly common in fast speech and can be confusing to non-native listeners in ESL contexts, who often hear words long before they need to spell them.