§8

In §8 you get an expansion of the language-game/language from §2. The expanded language is to contain number-words, 'there' and 'this' and colour samples. - The last on the list to be included - colour samples - is a bit unusual, perhaps. It isn't obvious that colour samples might count as part of a language. - Wittgenstein looks at this in a later comment.

Presumably the point of saying that the number words could be letters of the alphabet is to bring our attention to the use of number expressions.