Breakdown of Судя по его походке, он очень устал.
он
he / it (for a masculine noun) / it (for a neuter noun)
очень
very
устать
to get tired (perfective)
его
his / its (possessive)
Questions & Answers about Судя по его походке, он очень устал.
Why is походке in the Dative case here?
The phrase судя по (judging by) always requires the Dative case. Here, the feminine noun походка (gait or walk) changes to походке. The word судя itself is an adverbial participle (a verbal adverb) derived from the verb судить (to judge).
Why is the past tense verb устал translated as the present tense 'is tired'?
Устал is the past tense of the perfective verb устать (to get tired). In Russian, using the perfective past often focuses on the result of a completed action that is still true in the present. Because he 'got' tired, the present result is that he 'is' tired right now.
Is the comma after походке strictly necessary?
Yes. The phrase судя по его походке is an adverbial participle phrase (a phrase built around a verbal adverb). In Russian grammar, these phrases must always be separated from the main clause by commas, no matter where they appear in the sentence.
Why doesn't the possessive pronoun его change its ending to match the Dative case of походке?