Let me
Lemme
/ˈlɛmi/ElisionLinking
In real speech
What happens to the sounds
The t before m drops out and the words merge: let me → lemme.
When to use it
Very common in speech: Lemme see, Lemme think. Allow me is polite and formal.
Casual → formal
Slang
lemme
Neutral
let me
Formal
allow me
Sound notes
Elision: a sound disappears completely (often t, v, h or th).