Some phonological changes from Old to Modern English include the Great Vowel Shift, where long vowels underwent significant changes in pronunciation, such as the shortening of the vowel "i" in words like "bite." Consonant sounds also underwent changes, such as the loss of certain sounds like the "k" in "knight." Overall, these changes resulted in the modern English sound system we have today.

Because there are phonological variations in the way English is spoken, mainly due to geographic differences.

Phonological conditioning in English refers to the influence of surrounding sounds on the pronunciation of a particular sound. For example, the pronunciation of the "s" sound may vary depending on whether it occurs before a voiced or voiceless sound. This phonological conditioning can result in sound changes or alterations in English pronunciation.

The function of phonological rules in our life is to avoid misunderstanding and miscommunication words

No. The Navajo language does not have the English vowel U.

English does not have some of the Navajo vowels. Navajo vowels can be high tone or low or rising or falling if long. This change meaning in Navajo but only is used for questions in English. They can have nasalization which the French have but not the English. And they distingush between vowels held long or short which does not change meaning in English.

See related links for a list of Navajo letters and sounds.