There's a not-so-insignificant proportion of the population in Poznan that doesn't speak English.
Sure, some folks speak English, usually the young ones, and for the rest, there's Google Translate ... but if you really want to tap into this dating market, you'll want to learn Polish, preferably at the level of daygaming in it (which is basically fluent). This is similar to my experience in Makati in the Philippines - you can get by with English, but learning Tagalog will take your Game (not to mention your life) there to the next level.
Combining that with all the other observations I've seen, such as logistics, IOIs, etc., and these scout trips will also help me determine which language will be worth focusing on, for my planned July exodus from the 9 to 5 beta male rat race in FATlanta (that's not a typo, look at this timeline of obesity by US state since 1985 - the fatness came from the South:
Tomorrow: Sofia, Bulgaria. I'm excited to see this place, since I wouldn't be moving there just for the women, but also for the nearby skiing and not-too-far beaches, on top of the low cost of living.
I'm also excited to have Kiev penciled in for Thursday and Friday. As far as I've heard there's nothing there but the women, so I'd like to see if Ukranian girls are worth it, and especially to see if they react positively, negatively, or neutrally to me.