The translation that Knockernail has made is really good, I just change it a little bit.
BTW, read the lyrics thinking in two things:
1) tumbao is a way of walking, consequence of a rhythm.
2) tumbao is related to tumbas (tombs, cementery)
I don't know the cuban tradition, but maybe tumbao is a way commemorate the dead people.
That lil´black girl walking along
that lil´black girl has her tumbao
and when people go looking at her
she dances close by her side.
The blackgirl has tumbao
and she doesn´t walk by her side.
If you want to come right
better walk straight
just for no slips
and later come and cry.
If you want to come the first
better run slowly
enjoy well the life (darling)
although just taking measures.
Azúcar.
The blackgirl has tumbao
and she doesn´t walk by her side.
When people die (oh, my god)
it´s said that they were so good
so good when they were alived
as the night and the day (do you think so?)
I want they come to tell me the truth
I don´t bear more lies already (always the same)
enjoy well the life
although just taking measures.
Azúcar
The blackgirl ...
RAP
This lil´black girl has tumbao
everybody follows her by her walking.
Por cierto, ¿de qué parte de España sos Knock? Yo tengo conocidos en Murcia, La Rioja, Bilbao y Barcelona, es una de las pendientes viajar a tu país para visitarlo.