Lenition occurs after the words ar on, de off, den off the, do to, don to the, faoi under/about, ó from, roimh before, sa/san in the, trí through, um around/about.
don bhuachaill to the boy sa pháirc in the field</pre>
An exception is that words beginning with d, t, s are not lenited after den, don, sa or san.
den doras off the door sa teach in the house don sú to the juice</pre>
.. . 3 Preposition + Definite Article
Eclipsis occurs after certain prepositions where they are joined by the singular definite article an: .....
•E/L: In the standard, there is generally a choice between lenition or eclipsis after most prepositions + article .
e.g.: ar an mbord/ar an bhord = on the table
•E: In Munster and Connacht, one eclipses after most prepositions + article.
e.g.: ar an mbord = on the table
•L: In Ulster, one lenites after most prepositions + article.
e.g.: ar an bhord = on the table
Given the lack of context, “in jail” for sa phríosún should be acceptable. The difference can vary by dialect; for example, in the USA, “jail” can imply short-term incarceration in a county facility, while “prison” can imply long-term incarceration in a state or federal facility.
Jails are local law enforcement facilities designed to hold those awaiting sentencing, whereas prisons are facilities used for the longterm incarceration of those who have received their sentences. Prisons have more security levels. Many people use them interchangeably, which has become acceptable, but they're still different.
This confuses me a bit. I may be wrong, but I thought 'sa phríosún' would mean 'in THE prison', as opposed to 'i bpríosún' which would be 'in prison.'
Also, I know that in Ireland, certain institutions don't use a definite article when we do in the US, such as the Irish 'in hospital' as opposed to the US 'in the hospital'. Is this true for 'in jail' versus 'in the jail'? In the US, we would use the former, without definite article, typically.