A puzzle for de blog fans

Hewwo to my blog weadin fans.
Dis is a puzzle jus for you.
On Fwiday night, first my Gwandma and my Gwandda get in a car an dwive away.
Den my Mummy get in anuvver car and dwive away.
Bernie wait on fwont vewandah.
Heidi is somewhere outside in wain but Bernie do not know where.
De first person to come home was Gwandma.
She come walkin home wif her umbwella cos it wainin.
She say "Hello Bernie, do you want to come inside?" and she open dat door so Bernie can go in but he say "Meow wow" which mean "No fank you"
Can you guess why Bernie do not want to go inside?
I tell you tomowwow
Wuv fwom Bernie