1) Phonological processes are sound changes that occur in spoken language. This document discusses several English phonological processes including aspiration of consonants, flapping of /t/ and /d/, vowel lengthening before voiced consonants, and assimilation which causes sounds to become more similar to neighboring sounds.
2) The document also covers sound changes involving insertion, deletion, or modification of sounds within words through processes like epenthesis, metathesis, apocope, syncope, and apophony which involve internal changes to indicate grammatical information.
3) Examples of sound changes from other languages like Spanish and Tagalog are provided to illustrate how these phonological processes can vary across languages.