Particles (partikulas) are small, invariable words that add shades of meaning to a sentence or to a single word.
ne
not
arī
also, too
tikai
only
pat
even
jau
already
vēl
still, yet
vai
(question particle)
gan
indeed, (emphasis)
lūk
look, here
The particle vai turns a statement into a yes/no question.
Vai tu nāc?
Are you coming?
Viņš ir pat gudrāks.
He is even smarter.