As mentioned in another comment: it shouldn’t be. Youth culture has embraced this in part. However it lacks a certain finesse and makes it difficult for some people to differentiate on whether you wanted to use plural or singular for some people, especially in dialects which tend to omit the ending which would otherwise clarify the gender or singular/plural.

Edit:

Example: „Gibsch ma mal da Bleistift!“ (Singular) „Gibsch ma mal d‘Bleistift!“ (Plural)