Vayelech means, “and he went out/walked” referring of course to Moshe. The portion begins in a time of transition, where Joshua is brought forward as the next leader and final instructions to Israel are given. The portion ends with Moshe recording the words to a song, but those words are not given until the following portion, Ha’azinu.
Ha’azinu means “give your ears” or “listen.” It is the opening stanza of Moshe’s last song that he spoke of at the end of the previous portion. Although the language is poetic, the graphic imagery is meant for easy remembrance and its warnings are definitely LITERAL. There is no other poetry done as well in Tanakh except perhaps Job 38-42.
To these are combined separate Haftorah readings for it being the Shabbat of Return, the Shabbat after Yom Teruah but before Yom Kippur.