Because I can't! Apparently I called my mother "mommy" for the first two years of my life (as that's what she called herself) but then went to nursery and it became Mummy, and then later Mum, though it's switched back, but I refer to her as "my mum" or "my mother".
In US English the vowel sounds in "cot" and "caught" are the same - so words that are spelled as if they should be pronounced with a short /o/* are actually pronounced with more of an /a/. The sound isn't, however, quite like the British English "caught" so, as I notice that kind of thing, I notice that when I try to say "mommy" I don't sound like Americans do when they say the word. There are about 15 vowels in US English and 20 in British English, if you are interested. Unfortunately it doesn't make the job of learning to read or spell easier for US children as the phoneme**/grapheme*** correspondence is no more direct.
Since my mother gave up being Mommy quite some time ago, this wouldn't be a problem - if it weren't for the (no doubt annoying to mothers) habit of professionals who work with children of referring to the mother of the child as Mommy/Mummy. "Give it to Mum, now". "Let's see which doll Mummy has!". "Mummy, could you just open the box and show her what's inside?". I'm sure this grates just as much as "Ooh, you mustn't do X, it's bad for Baby". So shoot me, I can't always remember Mummy's name in the thick of a session. And you do need to use it to tell the child what to do: "Can you sit on Mummy's lap now and watch the pictures?".
So if you come across some confused children in this part of the world, it's probably because I'm getting involved in some assessment sessions with them...
Today's ICLW comments (it's I for International people NOT N for National, just saying!):
The Binky Diaries
Planning Doesn't Work
I Believe in Miracles
Production not Reproduction
If anyone knows of a way to track comments you have written - at least through Blogger - I'd be happy to hear about it. Just realised I commented on at least two of these already, not that it's bad but just like to spread it around!
*letters between slash marks = individual sounds in words, for the uninitiated.
**speech sound, which can be spelled with more than one letter
***representation of speech sound in letters, which can be more than one letter e.g. TH is just one sound, so is AW, and so is A_E as in GAME.