The grammarians, as many others (...), have their whims.

In English, sometimes one uses just a consonant, other times two identic.

In Portuguese, for instance, rarely a vocalic letter has its own and specific use: they write «Domingo» to mean the Sunday, but say «Doomingoo».

In Spanish, one respects the sound a little bit more. And the word is the same, in the given example. But things don't work like that at all.

I know grammarians have rules according with they establish a writing language. But many times rules are just freakishness there.

So, come on: simplify the writing of a language!