To A. H. Sayce   28 July 1877

Dear Sir,

It would be a great pleasure to me to give you any information, but I dare not trust my memory after so long an interval. In my little paper I have given only facts which were recorded at the time.¹ My impression however is that “mum” arose from opening & shutting the mouth repeatedly as a sign of wanting to eat, for this movement makes a sound like the letter m. I feel sure that several of the consonants (m, b & d being excepted) were much more difficult for my children to utter correctly than the vowels. I can only repeat my regret that I cannot aid you in your very interesting investigation.

I remain, dear Sir | Yours faithfully | Charles Darwin