Dia dhaoibh ar fad!

I'm very new to Irish and I found this forum a few days ago but now I am starting to read the grammar books and pay a little more attention than just to animal names and colours. I tried searching this forum for subjects that had "seo" and "anseo" in the title, but the message that popped up was that these words were too common and a search could not be returned. I don't think I will be the first person to ask this, but without being able to search more effectively, I thought I would just ask.

I learned "sin" means "there" and "seo" means "here" and then there is a use where you combine this with the definite article to get "this/that", such as "an buachaill sin" (lit. the boy there -> that boy) and a similar thing with seo/this.

But separately, I've seen "anseo" and I am not sure how it would differ from "seo" by itself. There is a note in Wikipedia about something to do with implied motion, but that didn't make sense to me without an example. I hope this question is the kind of thing that's okay to ask here.

Go raibh maith agaibh!
Alex

No, seo means "this" and sin means "that" and siúd / úd means "that" (in distance).

Well, "here" and "this" are related in meaning and there are situations seo can actually mean "here" on its own, but first of all it means "this".

You have to combine seo, sin, úd with the article to say something like "this/that boy" but that doesn’t change the verbatim meaning. It just means that a noun has to be already definite to attach seo to it:

buachaill = a boy
an buachaill = the boy
an buachaill seo = this boy



anseo means "here".
It is an adverb, obviously related to seo (verbatim anseo means "herein", "in this" because it is a combination of ann = in it and seo = this).

One way to understand these sorts of demonstrative expressions is to look at the way they evolved in Appalachian English in the US (heavily influenced by Ulster Scots speech, often with Gaelic roots):

an buachaill seo
this boy
Appalachian English: "this here boy"

an buachaill sin
that boy
Appalachian English: "that there boy"

The words ansin and anseo are, by contrast, used when the emphasis is on the location (as opposed to clarifying which person is meant):

Tá an buachaill ansin.
The boy is [over] there.

_________________
I'm not a native (or entirely fluent) speaker, so be sure to wait for confirmations/corrections, especially for tattoos.

Thanks, guys!

That's very helpful. It's good to know that "anseo/ansin" come from "ann + seo/sin" and the literal meanings.
I think I just thought it made so much sense to see how "the boy here" -> "this boy" and "the boy there" -> "that boy" made so much sense.
But I will try to rewrite my mental definition so that the primary definitions are this/that rather than here/there.

Go raibh maith agaibh!