There are a lot of these short words beginning with r in the Tiomna Nuadh, (the early 1600's addition). Can somebody give me a run down of what rolls they play? I got that (Riom = Liom, with me).

What are some of the other most prominent changes that I should know about whilst reading this text? (as compared to "Teach yourself Irish")?

Thank you... I appreciate you guys answering my nooby questions, it is really keeping me motivating to keep studying this beautiful language!!

riom = liom is a fairly huge simplification.

There used to be two distinct prepositions in Old Irish: fri ‘towards, against, to’ and la ‘with’. By Classical Gaelic times (1200s) they became re and le.

During the next few centuries they did mostly merge, so yes, they can be interchangeable to some extent in the 17th century Bible, but there’ll be traces of their difference and old meaning in there. They are still kept apart in Scottish Gaelic, by the way.

So eg. one is ag rá le duine éigin today, but this used to be rádh re ‘saying to’ (and still in Sc. Gaelic you have bruidhinn ri for ‘speaking with/to’).

Among some other things is the present (and future) tense having three endings, depending on context: cuiridh ‘he puts’, ní cuir (or ní cuireann) ‘he does not put’, réad chuireas ‘the thing he puts’ (and in the future: cuirfidh, ní chuirfe, réad chuirfeas). There are other differences in how verbs work compared to 19th and 20th century Irish…

You can find some of the stuff in my notes to Classical Gaelic (it deals more with older poetic language, but a lot of it is kept in Bedell’s Bible), and you can find some resources in this list of resources for Early Modern Irish / Classical Gaelic.