We would blend in with neanderthals pretty easily. But it isn't Angartyr's language skills that will matter, but rather his tracking abilities that are going to be useful. His language skills would probably be useful if he comes at the time of Julian the Apostate - while our protagonist doesn't speak Latin*, he does speak Greek, which should allow him to get by
somewhat. And of course, it would be useful in the Illyrian timeline, along with his skills in battle and leadership. Ancient Greece seems to be the best fit for our guy.
In terms of parlaying our skills to something useful, the Nazi timeline is probably the worst. While our hero is of fine Aryan stock, he speaks Old Norse. Worse yet, you don't bring a sword to a gunfight. But goddamnit, travelling in time in order to defeat Nazis before they summon the Great Old Ones is just such an awesome concept that I'm having trouble letting go of it, despite my better judgement.
Also note that choices 7 through 13 all are in Angartyr's time line, while only 14 would put us back into our timeline. This puts us in an interesting dilemma - we arrive too early, and we risk wiping ourselves out if we fuck with history too much. Arrive too late, and the Myrr family has already set their plans into motion and stopping the Great Old Ones will be even more difficult than the fuck-up we had just now. The sex change seems to be our best shot to set things right again.
* @
Cassidy, does Angartyr at least speak a little bit of Latin? I'd think that being surrounded by so many Christians would have at least exposed him to a little bit of it. If he sucks at speaking it, he ought to at least be able to understand some of it.