Is when a letter completely vanishes from a word. In Greek, an elision is marked by an apostrophe. A Hebrew example is the article which elides before a preposition; see here.
Is when a letter is present but is silent and is not pronounced. The letters alef, hey, vav, and yod can sometimes be “quiescent,” that is, silent under certain circumstances. video When an alef occurs without a vowel, then it is quiescent as in חַטָּאת.
Occurs when one letter is merged into another.
In Hebrew, the nun constantly assimilates as in the preposition מן; see here.
Some of the suffixes in the QTL verb forms have a ת. If the verb already ends in a ת, then the two ת join into one with a dagesh-forte. The verb כרת is an example.
The Hitpael stem also assimilates under the following circumstance. The “hit” prefix will lose its tav whenever it is attached to a verb beginning with a zayin, dalet, or a tet. video The tav becomes a dagesh in the first consonant (BBH 34.13).
First-nun verbs are notorious assimilators. video
No sufformative or pronominal suffix will ever assimilate.
and a poem...
Quiesce, Elide, and Assimilate
Went out for a stroll about half past eight.
Quiesce was seen, but never heard.
Elide disappeared without a word.
Whatever happened to assimilate?
A footprint dagesh points to his fate.