Scouse (/skaʊs/) is a local accent on the territory of the UK. It is also known as Liverpool English or Merseyside English, because it’s originating in the northwest county of Merseyside.
Liverpool is the centre of the Merseyside conurbation (population about one and a half million) and it has a long history as a major port with a famous seafaring tradition. It was the popularity of ‘lobscouse’ – a stew made of cheap meat, potatoes and ship’s biscuit – which gave rise to the inhabitants’ nickname of ‘Scousers’, and led to their speech being dubbed ‘Scouse’. Merseyside English sounds strikingly different from other types of northern English, probably as a result of a massive influx of in-migrants over the last three centuries from two Celtic countries – southern Ireland and neighbouring North Wales. 
Let’s examine how Scouse differs from other British accents.
1) /t/ [ts] TART
/t/ is pronounced with /s/ to make an affricate [t͡s] in Scouse: TEA, TALK, PART, WITTY.
«Time is taking its toll on Terry.»
2) /t/ [h] IT
In short words ending /t/ like IT, THAT, NOT the final /t/ can be [h].
«You’re not that good you know!»
3) /k/ [x] BACK
When /k/ appears in the end of a syllable in Scouse, it can be pronounced as a fricative [x] KICK, ROCK, BACKGROUND, BLOKE.
«Rick’s always on a break, he’s never working!»
«Look who’s talking!»
4) /r/ [ɾ] RIGHT
‘r’ is pronounced as a voiced tap [ɾ] RING, ARROW, FERRY, RIVAL – the tongue-tip touches the roof of the mouth behind the teeth very quickly.
«It’s rubbish! And very wrong of Rachel to write that.»
5) /θ/ [t] THANK, /ð/ [d] THIS
The ‘th’ sounds can be pronounced as a dental [t] and [d] in Scouse,: THINK, THEATRE, THOSE, BOTHER instead of dental fricatives /θ/ and /ð/.
«I think that’s their brother.»
1) /ɜː/ [œː] SIR
The vowel sound in BIRD is made with the tongue further forward and the lips a bit rounded in Scouse [œː]: SHIRT, SIR, TURN, WORLD.
«Bernard was the first person to learn the words.»
2) /ɑː/ [aː] HARD
In Scouse the long open vowel sound is made with the tongue forward [aː] in HARD, CAR, FATHER, PALM.
«Half of the party were in the bar.»
3) /ʌɪ/ [aɪ] WHY
In Scouse, this diphthong starts at the front of the mouth FLY, BUY, TIGHT, though if the word ends in a voiced consonant it can also be pronounced [aː] MINE, SIDE, TIMING.
«Try reciting this in time.»
4) /ɪ/ BIT
The vowel sound in BIT, WITH, BUSY is made with the tongue further forward in Scouse. It’s a subtle difference from GB, but it’s a very common vowel sound, so it’s pretty noticeable.
«This film’s a bit silly.»
5) /iː/ [ɪi] SEE, /uː/ [ɪu] POOL
In words ending with the long vowel sounds /iː/ or /uː/, the sound starts with an [ɪ]: BEE, FLEE, NEW, TRUE. This also occurs before /l/, so LIVERPOOL has a distinctive [ɪu] sound in the last syllable.
«It’s free to see the new zoo in Liverpool.»
6) Like other Northern English accents, /ʌ/ is not used at all, so FUN, SHUT, BLOOD, SON are made with /ʊ/.
Scouse intonation is clearly different from other British accents as it has more rising nuclear tones:
«She’s called Barbara.»
But the really distinctive feature is the Scouse melody which has a wide pitch range and a lot of high, flat tones after the main stresses. 
«It’s cold outside.»
«She’s called Barbara you know?»
«What time is it?»
Collins, Beverley; Mees, Inger M. (2013), Practical Phonetics and Phonology: A Resource Book for Students.
Hudson, Joseph (2019), Web-article Scouse – the Liverpool Accent https://pronunciationstudio.com/scouse-accent/