Do both of these mean "I think"? If so, is there any difference in how they should be used?
I have seen silim used to mean "I think" and "smaointe" meaning thoughts and found the root verb.

Faberm

I would say that "smaoin (ar)" carries more the meaning of reflection, and "síl" of holding an opinion.

Smaoiním ar mo mháthair - I think about my mother
Sílim go mbeadh sí sásta - I think she would be happy

A Abigail,

Poring into the matter I found that Irishdictionary.ie lists síl for seep/trickle, no mention of thinking on the verb side... while An Foclóir Beag gives these examples:

shíl mé nach dtiocfá; shíl tú mé a mhealladh

I understood them this way: I planned not to come; you planned to deceive me. In which I might be totally off the track.

There was no mention of seeping or trickling, so síl in AFB's sense would seem to be about planning.

From what I've read here I've understood that smaoinigh means an active process of thinking, and ceap would be more about having a gut feeling.

Obviously all of them have wider and partially overlapping meanings which I have to study deeper.

B'shin é an briathar "sil", is dóigh (.i. le guta gearr.)
Chì mi mo thriùir bhraithrean seachad
Air an loma luath
Sgeinean beag air bhàrr an uilinn
Fuil mo ghaoil a'sileadh uap'.

Tá éagsúlacht canúintí ann chomh maith. Deireann muintir Chonamara (nó cuid acu pé scéal é) "ag cuimhneamh ar" áit a déarfadh na hUltaigh "ag smaoineamh ar". ("Remember" an chiall is túisce a shamhlódh Ultach le "cuimhneamh ar".)

The Gaelic equivalent of "síl" (=to think -- opinion) is "saoil". As you say, Gaelic "sil" is as Irish "sil", ie. to drop, etc.

quote:

áit a déarfadh na hUltaigh "ag smaoineamh ar"

Rather "a' smaoiteamh ar" ;-)

There are many ways of saying "I think" in Irish.

Abigail has differentiated well!

I'd say smaoineamh is more abstract, síleadh concrete.

Nach ann don fhoirm eile (.i. do "smaoineamh") chomh maith, a Lughaidh? Níl na leabhra ar láimh agam ach táim réasúnta cinnte go bhfuil sé cloiste agam.

Ná ní fhógraítear an "g" sin i gConamara ach chomh beag.

B'fhéidir "smaoineamh" is like "to ponder" i mBearla. More ethereal.

B'fhéidir" "Síleadh" is just "I think" (similis, "cogito", ergo sum!)

Ceapaim go bhfuil sé agat anois, Faber!

quote:

Nach ann don fhoirm eile (.i. do "smaoineamh") chomh maith, a Lughaidh? Níl na leabhra ar láimh agam ach táim réasúnta cinnte go bhfuil sé cloiste agam.

Char chualaidh mise ó dhaoiní as TC é, go fóill. Is dócha go n-úsáideann daoiní áiríd é, go háiríd daoiní atá faoi anál Ghaeilg TG4 nó Ghaeilg na scoile srl.



Smaoiním > I reflect, I turn something over in my mind

Sílim > I think that..., I believe (that...), I'm in the opinion that...

The first one is just the action of thinking. The second is used to say what your opinion is.