'Fy nhalu (i)' means 'my paying'. Or, if you're referring to what the comment means, I'll give it a go :).
So, I love this course, as it's teaching me a lot of useful vocal and phraseology. However, something it doesn't go much into, and a major feature of Welsh (and other Celtic languages) is a change in the first letters of some words that's called 'mutation', because the first letters...well, mutate. Specific letters undergo different types of mutation under certain grammatical/syntactical circumstances, and the possessive pronoun 'fy' meaning 'my' is one of these.
'Fy' causes what's called a 'nasal mutation' (as opposed to 'soft mutation, 'aspirate mutation", and 'mixed mutation' - I won't go into all of these now). So, put very simply, this (rather rare, 'soft mutation' being the most common) nasal mutation turns an initial 't' into an 'nh' (obviously... :/ ). Thus, the word for 'paying', 'talu' must undergo 'nasal mutation' after 'fy', rendering it 'fy nhalu'. The word for 'family', 'teulu' would be the name. 'My family, would be 'fy nheulu'.
The word 'yn' meaning 'in' (a city, country etc) also triggers nasal mutation. Thus the phrase: 'in Wales' would be the word 'yn' + 'Cymru'. A 'c', nasally mutated, as it were, converts to an 'ngh' (which looks bonkers to what we're used to in English, I know, but it's definitely part of Welsh's charm, in my view). So, 'Cymru' after 'yn' (when it means 'in', not the 'yn' before verb-nouns) turns to 'Nghumru'. However, in this circumstance the 'yn' assimilates to 'yng', too, so what we have is 'yng Nghumru'. Looks mad, I know, but it's actually quite clever, as it often represents what happens in speech naturally. In English if we say 'in Cardiff' quickly, broken down phonetically, it would sound a little like 'ing nghardiff'. It's just that Welsh chooses to represent it orthographically, and there are set rules to it :).
I hope that's cleared it up a bit. It seems daunting at first, but it'll become second nature with practice. Check the link below for a more details explanation of mutation:
I hope you don't feel too mutated after my convoluted description :p.
Thanks for this. I'm aware of soft mutation and applying it correctly is a work in progress...I just meant that "my paying" doesn't make a lot of sense in either English or Welsh as "paying" is a gerund form of a verb and not a noun. Unless you're using it in a relatively old-school way "he didn't mind my paying for the beer", asking us to translate this is a little nuts.
Your confusion is understandable, because it doesn't make much sense in isolation. But it can appear in a sentence in a number of ways.
Here are some examples: 'Ces i fy nhalu' is the passive voice construction for "I was paid"
'Mae e'n fy nhalu' or "Mae e'n fy nhalu i' = "He is paying me" This is one of the charming aspects of Welsh. When the direct object of a sentence is a pronoun, the object "possesses" the verb, so to speak. "dw i'n dy weld di" is another example that you may have already encountered.