My 6 month old DD holds her thumb in her fist a lot of the time when at rest. She can open up her hand and bring out her thumb when she is reaching for things, though regularly holds her thumb in her palm when she is grasping, particularly for smaller toys. Should I be concerned? She is generally meeting all her other milestones though is not yet making consonant sounds. I have been reading that the thumb in fist posture has been associated with language delays and I have noticed that some autistic children do this. Does anyone have any experience of this?