This is how what the man said can be written in phonetic text (see
list of the sounds here).
Notes:
yes-ai
= "Yes I", the S Sound at the end of "yes" is pronounced as a
starting consonant of "I", hence the dash.
be·ə
= "better", two syllables with accent on the first, no T Sound
or D Sound.
giv
ə = "give the", the Thorn Sound of "the" is
pronounced as a V Sound in cockney. To avoid having two V
Sounds together which would result in a stop, only one is
uttered.
doi·næm·ik
= "dynamic", three syllables, the O-I Diphthong is used in
the first syllable instead of the middle-class A-I Diphthong.
duu·wou
= "duo", two syllables, the first containing no Y Sound,
unlike in middle-class speech.
wə = "a", the W Sound
is an added consonant to avoid a stop between the
O-U Diphthong ending the previous word and the Schwa
Sound of "a", which are both vowel-sounds.
koo‛w
= "call", the final Dark W replaces the Dark L of
middle-class speech.
The "dynamic duo" is
the man's jokey way of calling the two men who are to 'repair'
the two weapons.