English letter sequence with most pronunciations
Answer to (2):
We memorize each exceptional word. In the grand scheme of things, this is actually not a huge number of words. Consider Chinese and Japanese, who have a large number meaning-based characters that provide little to no information about their pronunciation at all. If memorizing the pronunciation of thousands of characters is possible, then memorizing English words with exceptional spelling seems almost trivial.
It doesn’t surpass it, but ue seems to at least be a modest little brother to ough. It can represent:
- \-yoo\: argue, cue, ensue
- \-oo\: glue, true, sue
- [silent]: tongue, morgue, vague, the Hague
- \-way\: segue, suede
(This is just looking at the cases where it really is functioning as a unit, omitting examples like truer and queer, where a phoneme straddles its boundary.)
[Inspired by the comments here.]
"al" can be pronounced
- /ɔ:l/: all, also
- /ɒl/ or /ɔl/: false
- /ɔ:/: talk
- /a:l/: dal, kraal, phall
- /a:/: half, calm, almond
- /əl/: usual, alone
- /æl/: analysis
- /æ/: salmon
- /eil/: halo
- /ei/: halfpenny, Ralph (by some)
OK, the case for /a:l/ is pretty weak -- I can't think of any examples except direct loans.