Your use of "chuig" together with the dative case is good. Just a few points to note: - "siopa leabhar" rather than "leabhar siopa" (which would mean "a shop book"), I suspect this was just an error of distraction. - Sin an trá álainn a ndeachaigh mé chuici anuraidh. - Seo an trá álainn a ndeachaigh a mhic chuici anuraidh. - Chuaigh mé chuig trí thrá áille [the adjective is plural after most numbers] mar ar féidir snámh le deilfeanna [here you need an indirect relative: "...where it is possible"]. "Trí" lenites any lenitable consonants if the following noun is singular. If you use a plural noun after it, though, it doesn't lenite (e.g. trí cinn, trí bliana). I find constructions like "le cara leis Dan" and, especially, "dúirt cara liom Jake liom" a bit strange, but I realise that I myself told you to avoid using "mo chara". Well, I've been thinking about that and I'd just like to revise and correct what I told you before. When you say "mo chara" it means a definite friend; semantically, it would be equivalent to something like "the friend of mine" in English, so if you say "Bhuail mé le mo chara inné", it seems like the friend you met is your only friend (or else this friend is already the established topic of conversation). In cases like this, it is better to use "cara liom" (or "cara dom" or "cara de mo chuid") to show that you are talking about an indefinite friend, one of many. However, when you actually name your friend, e.g. "my friend Jake", then that *is* a definite friend, so in these cases it's fine, and indeed usual, to use "mo chara". So you would have "...lena chara Dan", "...lena cara Amy", "Dúirt mo chara Jake liom...". Sorry about confusing and misleading you before, I hadn't thought it out well. You could also say "le cara leis darb ainm Dan" if you want to express "a friend of his called Dan".

Does trĺ cause lenition even on words beginning with a t? If so, then I should have written "trĺ trá".