1. CPC and Positioning: Here is some detailed info on qualityscore: https://support.google.com/adwords/answer/2454010?hl=en it will help raise your add position without raising your price (depending on competitive factors)
2. Linguistic Differences: Noted just wanted to cover all our bases!
4. Conversion Opportunity: Excellent! Consider linking your Adwords and Analytics to run A|B testing on a landing page for your Ad as well!
Yeah it certainly sounds like your campaigns are going to cost more in these regions! In your Google Adwords dashboard on the 9th column to your right, you will see "Avg Pos" this is the average position which the ad appears. Just like Google organic search lower position means less visibility and less clicks by an exponential factor. The first 3 ads display above the organic results and get roughly 60% of the ad clickers, and then 4-10 sit to the right of the organic results and get the other 40% (diminishes quickly). Anything below 10 is seen only if the user goes to the 2nd page or further.
Your average position will be expressed as something 2.7 it's an average of all the times you appeared. This is a good indicator that you may need to increase your bid and your qualityscore.
You can check your QualityScore by hovering over your keyword in the dashboard to see its performance results!
Best of luck!