John 1:27

ὁ ὀπίσω μου ἐρχόμενος, οὗ οὐκ εἰμὶ ἐγὼ ἄξιος ἵνα λύσω αὐτοῦ τὸν ἱμάντα τοῦ ὑποδήματος.

ὁ definite article nominative masculine singular "the"

ὀπίσω adverb "behind/after"

μου personal pronoun genitive singular "of me"

ἐρχόμενος present middle deponent participle nominative masculine singular from ἔρχομαι (I come) "the one coming"

οὗ relative pronoun "who"

οὐκ negative particle "not"

εἰμὶ verb present indicative 1st singular "I am"

ἐγὼ personal pronoun nominative singular "I" (note: emphasis)

ἄξιος adjective nominative masculine singular "worthy"

ἵνα conjunction subjunctive "that"

λύσω verb aorist active subjunctive from λύω (I loose) "I might loosen"

αὐτοῦ pronoun genitive masculine singular "of him"

τὸν definite article accusative masculine singular "the"

ἱμάντα noun accusative masculine singular "thong"

τοῦ definite article genitive neuter singular "the"

ὑποδήματος noun genitive neuter singular "sandal" (Note: 3rd declension 3rd subgroup ending)

Rough Word-by-word:
The behind/after me one coming he not I am I worthy that I might loosen of him the thong of the sandal

Smooth Translation:
I myself am not worthy that I might loosen the thong of the sandal of he who is coming after me.

(Note: To me changing the order of the clauses seems to make the English easier to understand)