With insertion, sounds are added to words that are not apparent in spelling or slow pronunciation (Scramm, 2001). This can provide confusion to learners of a new language since the way they are instructed to pronounce certain words do not correspond to how they perceive the words visually. A couple of examples of insertion in the English language are words like "hamster," which is usually pronounced "hamster," or "month," which is usually pronounced with an exaggerated "t" sound - "mon-t-th" (Scramm, 2001). The final category of phonological rules is deletion. This type of rule deals with processes of pronunciation in which sounds are left out, or deleted (Scramm, 2001). With the process of deletion, confusion may arise when the pronunciation of a word diverges from the way it is spelled and becomes very similar to the pronunciation of another word with completely different meaning. An example of this is the word "police," which is often pronounced as "pleace," which is furthermore very similar to the word "please."

Traditionally, it was widely believed that lexical access from print always involved phonological processing, which occurred automatically (Ferguson, 2006). However, Ferguson (2006) established evidence contrary to this belief in which lexical access was shown to be accomplished through orthographic processes without phonological processes. This is only true for intact skilled readers though, and would not be the case for individuals who are learning a new language.
References

Johnson, M. (1984). A discovery procedure for certain. phonological rules. In COLING-84, Stanford, CA, pp. 344-347.

Ferguson, R. (2006). Basic processes in reading: Can Functional Phonological Recoding be blocked? Canadian Journal of Experimental Psychology.

Schramm, a. (2001). Phonological Rules. Retrieved 6/09/2007 from http:www.hamline.edu/personal/aschramm/linguistics2001/9phonrlz.html.