Most Polish speakers do the following things when they speak English:
1. Confuse E and IH (say sight or sit)
2. Say EH instead of AH (say bet instead of bat)
3. Say EW instead of OOH (say Luke instead of look)
4. Say O instead of OW (say no instead of now)
5. Say UH instead of ER (say but instead of Bert)
To address these mistakes practice the following sounds:
E, IH, AH, OOH, OW, ER