a plum in your mouth
US /ə plʌm ɪn jʊər maʊθ/
UK /ə plʌm ɪn jʊər maʊθ/

1.
ter uma ameixa na boca, falar com afetação
an affected way of speaking, as if one has a plum in one's mouth, often associated with upper-class accents
:
•
He speaks with a plum in his mouth, making him sound very aristocratic.
Ele fala com uma ameixa na boca, o que o faz parecer muito aristocrático.
•
Her affected accent sounded like she had a plum in her mouth.
O sotaque afetado dela parecia que ela tinha uma ameixa na boca.