In many Canadian and American dialects, the low front and mid front vowels diphthongize before the voiced velar plosive. The voiced velar plosive occurs in the same syllable. The diphthongization of the vowel does not occur in other dialects of English.
Words such as egg and leg can be pronounced with the diphthong of day rather than the mid front lax vowel of ten. Likewise, words such as bag and flag can be pronounced with the diphthong of right. Before the voiceless velar plosive, diphthongization does not occur.
Diphthongization can also occur before the velar nasal in words such as bank and sang. The velar plosive and velar nasal have the articulatory feature +high, a feature that is also present in the second component of the diphthongs. It can be considered a type of partial assimilation.
Diphthongization of the low front and low mid vowels before voiced velar plosives occurs in the English of many Canadian and American speakers. The process is a type of regressive assimilation. The velar consonant creates the environment for diphthongization. The process can also be considered a type of palatalization.
