As nouns the difference between lah and lai
is that
lah is an alternative spelling of lang=en while
lai is a mostly North European form of medieval song, with stanzas that do not repeat.
As a particle lah
is , Placed at the end of a sentence either for emphasis or reassurance.
As an initialism LAH
is lithium aluminium hydride.
As a proper noun Lai is
a Tibeto-Burman language of India and Burma.