to
/tu/9 verbsThe thing the action points at, sticks to, or is measured against.
TO rarely stands alone as the whole particle. It usually arrives as the third word — look forward to, look up to, stand up to, wake up to, talk down to — where it attaches the object to a verb that already has a particle.
The trap with look forward to is grammatical, not phonetic: the TO here is a preposition, not an infinitive marker, so it is followed by a noun or an -ING form. “I look forward to meeting you” is correct; “to meet you” is not.
What it does to the sound
TO reduces to /tə/ in connected speech — never the full /tu/ of the standalone word. After a vowel it can flap: look up to it runs together as “loo-ku-də-dit”. Giving it a strong vowel is a reliable sign of reading rather than speaking.
What TO means
Attachment — stay fixed to something
You adhere to a plan, rule, choice or person.
Orientation — face something
The verb already has a particle; TO names who or what it is aimed at.
Every verb that takes TO
The complete list — 9 of them. The section above groups the common ones by what TO is doing.