By the same token I'm keeping the guidelines for Mighty Deeds of Arms in the back of my head -- way in the back. I prefer to wing it a little more. The guidelines are more important for people used to doing things in 3.5 and Pathfinder. While I have been playing those, I also have a healthy dose of experience with AD&D2e and BECMI D&D, and absolutely love Swords & Wizardry. Wanna do some cool combat move that's not in the rules, make it up! So that's the way I run with Deeds.
Starting my campaign tonight, in theory, btw. There's a group of friends we don't see very often whose GM got to go to GenCon and who all didn't for various reasons, mostly money and kids, like us. They are thinking of doing a board game night tonight, while my significant other really wants to roleplay, so she's rolled up SIX 0-Level PCs and is chomping at the bit, hoping to convince everyone else. As for Demi-human languages, I will be going with the book on this after all, as I've decided all the 0-Level characters are from the same village, and there's not exactly a bilingual educational system in place, so their parents have been bringing them up speaking Common so they can interact with the other villagers. The bright ones learn their racial language. If the characters were from more wide-spread backgrounds, they might speak their racial tongue instead, and only know Common if they were intelligent enough.
Guess I went a little off-topic here, but I'm illustrating how I handle the system as a whole -- fast and loose, subject to Judge interpretation as fits the needs of the story.