1) Weak forms occur when commonly used words like prepositions, auxiliary verbs, and conjunctions are unstressed in connected speech. Their vowels shift towards a schwa sound.
2) Yod coalescence is a phenomenon where /j/ assimilates to a preceding /t/ or /d/ sound, like "but you" becoming "bətʃu".
3) Elision omits sounds like consonants between consonants and the /t/ in "not" before consonants, speeding up connected speech.