[Conscientious]

Guys

naif and English boy , u r both right

the accent means لكنه
and it is the differences between the prognostication only

for example the pronoun (me ) can be pronounced differently in Britain and America , that's why we always say British accent and american accent

however

the dialect means( Lahja) and it is the differences in the lexical items(words) , that's why we always say Saudi dialect , Sudanese dialect ..etc

i remember we study this in the Introduction to linguistic

so i think in this youtube he mentions both dialects and accents

for me i think that foreign people who are speaking English are speaking actually different Accents like Indian , Chinese ...etc)a

but

British people who are from different reigns in UK are actually speaking different dialects

Good luck