speaker option enabled by default when answering the calls Can any of the applications change the call settings? All of a sudden have observed that when an incoming call is answered, Speaker is enabled by default.

After uninstalling some of the applications related to calls, it became normal.
But I would like to know what/which caused the change in settings.
Apps I deleted are TrueCaller, Call Recorder.

Any information related to this is helpful. Thanks in advance.

Samsung Galaxy Note 2 running 4.1.2 JellyBean.
I know for certain that some apps do have the option of changing the setting (e.g. InDrive allows you to switch to speakerphone when driving)

As for the second question, I believe that CallRecorder is the culprit, because:
a) I have tried TrueCaller once, and did not experience anything like you are mentioning,
b) Call recorder apps generally can't work on unrooted Android (as far as I know) unless you are using the speakerphone, so that they can record your voice, and the voice coming from the speakerphone.