突然彼らは笑い出した。

突然彼らは笑い出した。

All at once they began to laugh.

突然(とつぜん)彼(かれ)らは笑(わら)い出(だ)した。

Totsuzen karera wa waraidashita.

突然 (とつぜん)

abrupt; sudden; unexpected; all at once

彼ら (かれら)

they (usually male); them

は (は)

topic marker particle; indicates contrast with another option (stated or unstated); adds emphasis

笑う (わらう)

to laugh; to smile; to sneer; to ridicule; to be dumbfounded; to be flabbergasted

Readings: トツ、カ、つ.く

Meanings: stab, protruding, thrust, pierce, prick, collision, sudden

Readings: ゼン、ネン、しか、しか.り、しか.し、さ

Meanings: sort of thing, so, if so, in that case, well

Readings: ヒ、かれ、かの、か.の

Meanings: he, that, the

Readings: ショウ、わら.う、え.む

Meaning: laugh

Readings: シュツ、スイ、で.る、 -で、だ.す、 -だ.す、い.でる、い.だす

Meanings: exit, leave, go out, come out, put out, protrude