John 1:37

ἤκουσαν οἱ δύο μαθηταὶ αὐτοῦ λαλοῦντος, καὶ ἠκολούθησαν τῷ Ἰησοῦ.
they heard the two disciples of him when he was speaking and they followed the Jesus.

ἤκουσαν verb aorist active indicative 3rd plural from ἀκολουθέω (I hear) "they heard"

οἱ definite article nominative masculine plural "the"

δύο numeral "two"

μαθηταὶ noun nominative masculine plural "disciples"

αὐτοῦ pronoun genitive masculine singular "of him"

λαλοῦντος verb present active participle genitive masculine singular from λαλέω (I speak) "when he was speaking"

καὶ conjunction "and"

ἠκολούθησαν verb aorist active indicative 3rd plural from λαλέω (I follow) "they followed"

τῷ definite article dative masculine singular "the"

Ἰησοῦ proper noun dative masculine singular "Jesus"

Rough Word-by-word:
they heard the two disciples of him when he was speaking and they followed the Jesus

Smooth Translation:
The two disciples of him heard when he was speaking and they followed Jesus.