IBM Software Developer interview questions

one phone interview. The interviewer is the project manager from the department I applied for . He is nice .The questions he asked are very easy , but my english is not fluent . Sometimes I know the answer but cannot speak it out fluently . I guess that is the reason I failed the interview

asked some design pattern problems, data structures and multi-threading, and asked to introduce working experience. the problems you have met and how you fix it.