Why do my younger friends never understand a text?

You need to ensure that you are using the correct grammar.

'Good Kinsman Of This Fair Borough

Prithee, wilt thou give unto me fair passage this St. Swithins?

Shalt we findan aet 'The Lamb & Flag' Frigeaefen?'

I rarely get replies, for some reason...

I'm not sure what you might be saying that could be a mystery to them. Could it be because you write in full sentences and spell things correctly?

I need an acronym guide I can’t keep up

You are among us in the generation that communicates in words and sentences. Young people don't understand that. They communicate with abbreviations, acronyms and symbols we old folk used to call punctuation. It's a different language. It's not your fault.

I won't respond to that kind of text

huh☺

What?

And we wonder why they are failing education

What do you mean?

It’s their loss I guess.