I just wanted to post a quick note to anyone who may be having this problem.
I recently purchased the Huawei 5W phone and was having problems with the speaker phone causing horrible echo to the person on the other end of the conversation. Anyway, after doing some trouble shooting, cache reset, factory reset, uninstalling apps, I have found that removing Google Talkback from the phone stops this issue.
I hope this information helps someone as it has been a week long frustration I have had since getting the phone.