Sorry if this topic has been raised before, but I have noticed as I start getting into reading contemporary Welsh novels not specifically aimed at learners that while the narrative may be written in a fairly regular sort of Welsh, the dialogue (which I assume to be realistic) is often heavily peppered with purely English words simply given a Welsh spelling. This seems particularly true when teenagers are speaking. For example, within the space of a few pages I find blwmin, blincin, boncyrs, feirws, brĂȘn, miwsig, prat, crap, cym on, fflipin, stwpid, stwbwrn, absoliwt, bisĂąr, bĂȘb, sili and hangover (surely the Welsh must at least have their own word for hangover!). Is there any way of knowing, other than by long experience, which of these anglicisms are an accepted part of the modern language and which are going to make you sound a bit of a wally? Is it best to steer well clear of them or conversely, if you always try to stick to native Welsh words, are you going to sound a bit stilted or affected? Is âcerddoriaethâ, for example, the perfectly neutral proper word for âmusicâ or is it being ousted in speech by âmiwsigâ? Would a careful speaker always use âymennyddâ rather than âbrĂȘnâ? Is âystyfnigâ (or âstyfnigâ) now a bit literary in speech compared to stwbwrn? And so on.
Pen Mawr is hangover in Welsh, but Iâve used this before with friends and they donât know it, theyâd only say hangover.
On the whole, the normal âdonât worry about itâ is the rule to follow here.
English words pop up all the time. Cerddoriaeth and miwsig are both used. For example, there is a day next Friday âDydd Miwsig Cymruâ.
Of course, using the actual Welsh word is absolutely fine and, using it is the best way to find out how others feel about it 
Itâs a minefield for the learner. We know there are Welsh words for things but that people often use Wenglish or Anglicisms.
I think itâs a product of being genuinely bi-lingual, where you can choose the word or phrase you prefer from either language, or the one that is easier /quicker to say, such as âmiwsigâ. I suppose itâs a bit like you learn playground slang at school, but have also learnt to âhow to speak properâ to your grandparents. Itâs probably much the same.
As a learner it will be a long time until I am comfortable being bi-lingual in this way. I donât want to be language police or anything. I was chatting at an Eistedfodd and they used the word âtentâ, In my next sentence I said âpabellâ and they were like âoh sori pabellâ, it was an awkward moment, it felt odd to have inadvertently corrected a fluent speaker, when Iâd only been learning for 6 months.
A decent rule of thumb would be that if you see one in a book, the author at least thinks itâs in common usageâŠ
Not sure Iâd get away with using teenage language. âCos Iâm old enough to be a grandad⊠in fact I am one, now that I think about it!!
Itâs been happening for a long time, this mucking about with foreign words. Apparently some French aristocrat was gifted some land on Anglesey at some stage in the historical past. When he came to view it, his reaction was âOh, what a beautiful marsh!â. Except he said it in French - âQuel beau maris!â. And so, dear reader, it became known as Beaumaris, or Biwmaris as it is more Welshly known today.
True story.
My fave word ever. 
Thanks for responses. I find it interesting that in a book Iâve just been reading, a Welsh-speaking teenager has to ask the meaning of the Welsh word âcildwrnâ, and has it explained to her as âTip. Arian i ddiolch am gwasanaeth daâ, to which she replies âO, dwiân gwbod beth yw tipâ. I have a feeling Saunders Lewis would not be happy about thisâŠ
I think a lot of these happen just due to the bi-lingual nation thing and the fact that Welsh and English languages live in such close proximity.
My Welsh is far better than my French for example, but I find that I never ever use any âanglicismsâ in my French speaking when Iâm out there and I canât remember ever doing so - if I donât know the word Iâm looking for, then Iâll go around the houses and describe it in some long winded fashion - however with Welsh if I donât know the word, I wonât spend ages looking for it in my head, Iâll tend to use an English one to allow the conversation to continue.
Itâs a weird one that Iâm sure some language expert could explain (maybe!)
Anglicisms are extremely common in everyday speech and emails - and not just limited to teenagers. Even in work I often hear/see/use âjestâ(just), ârĂźlĂźâ(really), âplĂźsâ(please), ânytsâ(nuts), âenigwdâ(any good), and many more.
However, thatâs not to say that these anglicisms are used all the time in preference to the Welsh - and certainly rarely in formal discussions/emails/etc.
Whilst I do understand the argument for using proper Welsh words and shunning the anglicisms, in practice using anglicisms here and there will make you sound more of a natural Welsh speaker and less of a learner.
I often say âgwd diolchâ in response to âtiân iawnâ oâr something. I blame @iestyn for âforcingâ to spend so much time in Ceredigion.
Oh, I feel your pain. Nothing more worrying than realising that youâre picking up Iestynisms⊠
I mentioned elsewhere that, in France and en route on the Ferry, faced with a forgotten word, my brain, told ânot Englishâ would toss up the Welsh word. Now, I tend to find French words coming into my head if I am trying to think in Welsh If you know you are with bilingual Welsh/English people, you are bound to grab whichever of those arrives in your brain!
Been here long enough to call myself a Cardi now!
Pipe down! 
This happened to me when I placed an order by phone. I said Iâd like to archebu a couple of t-shirts and the person replying, asking what I would like used ordero.
So as you say, itâs very common in everyday speech and youâll see it in TV interviews etc as well as hear it in the street and shops.
And I missed another extremely common one⊠âsoriâ(sorry).
There are so many though.
âsciwsio fiâ (excuse me)
âniwsansâ (nuisance)
âlyfliâ (lovely)
The thing is, many never look like anglicisms when written - âlyflijybliâ(lovely jubbly) for instance - which is frustrating when you read it, then spend time failing to find it in a dictionary only for it to dawn on you later what it actually is. Unless youâre reading out loud, when it generally becomes obvious sooner!
Iâm half way through writing my first novel. Itâs contemporary, has a lot of dialogue, has some very colourful characters and the setting is loosely based on the Caernarfon area. So it is full of this kind of creative language.
I wanted what I wrote to be real, believable and reflect modern society as we know it. So the dialogue is (hopefully) what you would hear on the streets and therefore contains Anglicisms (Wenglish), spelt in sometimes obscure ways and making creative use of circumflexes. It also has a fair sprinkling of swearing!
But much of the language in the narrative is traditional and can contain quite formal language in places. Iâve tried to make use of a rich vocabulary making use of some older verbs and adjectives which may not be so familiar.
I agree very much with what Siaron says hereâŠ
Thereâs a Welsh Youtuber out there (Wales Shark) who hasnât really done any videos in years. However one of his videos touches on his favourite Welsh words, and thereâs a bit where says something likeâŠ
"ffrwchnedd: which is âbananaâ in Welsh. The only time I have ever heard someone actually say ffrwchnedd in Welsh, is when someone has said âI have never used the word âffrwchneddâ for bananaâ
:D:D:D
Rightly or wrongly, and not caring if I sound like a learner, I will always try to use the Welsh word even if the person Iâm talking to doesnât. Fighting a losing battle? Maybe. Give up the fight? Never!
I find there are a few Greek words that come to mind when I want Welsh ones - but always and only those with Greek sounds that are (more or less) also used in Welsh. So I never think of saying ksanĂĄ for âagainâ, because ks- on the start of a word is as un-Welsh as it is un-English: but Ăźcha for âi hadâ sounds very nearly Cymraeg, and has the added advantage of being much more like the English grammar than oedd geni. And so itâs the first thing on the tip of my tongue every blominâ timeâŠ
Iâm going to point and shout the next time I hear you say âoceâ, then.