The Back Story (fiction alert)

The people of the valley, having never encountered anyone who speaks
differently than they do, had no word for "language". Their root for
"word" is simply sa, and the ending for mass nouns is -am, so the
closest thing to "language" would be saam, meaning "speech". It is a
mass noun, a noun that cannot have a plural, because the people of the
valley could not even conceive of having a plural for "language"
since, to them, there could only ever be one way to speak.

The language has an adjective for "all", or "every", which is gule.
The people of the valley refer to themselves as gulam; "everyone", or
"everything". After they made contact with the outside they called
their speech Saam Ugúlam; "Speech of everyone".* This, then, is the
name they use today for their language.

* It should be noted that the possessive particle U denotes "of", or
"belonging to". The people of the valley use only crude pictographs as
memory aids, and have no systematic writing. Scholars using the Roman
alphabet disagree as to whether U is a separate word, or a prefix on
the following noun. Some transcribers write it as a separate word and
some write it as a prefix. You might, therefore, see Saam U Gulam or
Saam Ugúlam. Since there is no consensus as yet, and since it sounds
to my ears like a single word, I will write it as Saam Ugúlam until
such time as a consensus emerges, after which I will conform to that

---More, basic phonology, how to pronounce doubled vowels, etc. and
the first 28 sentences of McGuffey's at the link