Languages can grammaticalize a lot of different things. Japanese grammaticalizes the shape of an object with a noun suffix. Turkish grammaticalizes how certain you are of a statement with a verb suffix.
English doesn’t grammaticalize much. We just use extra adjectives and adverbs. However, I predict English will acquire a feature in which it grammaticalizes mood with a sentence-final clitic. For example, compare:
In example 2, the sentence-final ‘lol’ marks the sentence’s nonserious mood, making it apparent to the listener that he is in fact being mocked, rather than informed of his condition, as in example 1.
The mood indicated by ‘lol’ does not have to be mocking, however. It can encompass a wide variety of situations, including smugness, irony, amusement, even to defuse an otherwise inflammatory sentence. Consider the following statements:
Example 3 is read with a default mood of meanspiritedness or frustration. Grammaticalizing the nonserious mood here serves to obscure whether or not the speaker actually thinks Jake is a pansy. In such cases this grammatical structure will also provide plausible deniability should Jake take offense anyway.
The use of a clitic to grammaticalize mood in English will not necessarily be limited to the nonserious. Consider the tone presented in these examples by other possible sentence-final mood markers:
Undoubtedly the anglophone population is rapidly progressing towards an ever more useful and versatile language. God save the queen lol.