I didn't think anything of it but now an increasing number of people are commenting on the high pitched squeals he makes ALL day and saying how strange it is. Also he doesn't babble like the books explain - no real vowels/consonants - just shrieks at the very top of his voice. I am now getting paranoid about it and thinking there is something 'wrong' with him, whereas in all other respects he meets the milestones that the books say he should be. Am I being stupid or is this something to worry about?