'll

1a The contraction 'll can be suffixed to all the pronouns in writing. It's added directly to pronouns that end in a vowel. Phonetically, this results in (1) a dark, approximant [ɫ] sound at the end of these words, and (2) in conversational or rapid speech, a reduction of that vowel or diphthong. Thus, the form he'll tends to sound like heel in careful speech or when emphasized, and like hill in normal or rapid speech. 

1b In writing, the suffix 'll isn't normally added to nouns and names that end in a vowel, but in speech, a reduced form of the word will is used. This reduction is pronounced [ʊɫ] (and in some speakers [ǝɫ]) and it's pronounced as a separate syllable. In other words, it takes up the same space that the unstressed word will would. 

Note that words that end in a diphthong containing [i], like bowtie [bóu̯tʰài̯] and Eli [ílai̯], change this [i̯] into [y] in front of the reduction [ʊɫ]. Similarly, words that end in a diphthong containing [u̯], like Moscow [mɑ́skæ̀u̯] and potato [pʰǝtʰéi̯ɖou̯], change this [u̯] into [w] in front of [ʊɫ].  Note that the resulting [wʊɫ] sounds quite similar to the full form [wɪɫ] and will barely sound like a reduction.

2 After words ending in consonants, the reduction [ʊɫ] is simply used in the place of unstressed will [wɪɫ].