To fall asleep?
Me quedo dormido
Me caigo de sueño

Do these two phrases have the same meaning? Are they used interchangeably? Thank you for clarifying.

Question

To fall asleep?
Me quedo dormido
Me caigo de sueño

Do these two phrases have the same meaning? Are they used interchangeably? Thank you for clarifying.

Answer

Son parecidas, pero no significan la misma cosa. Mira estos ejemplos:

Mi trabajo demanda gran esfuerzo fisico. Después de cenar siento que me caigo de sueño. Cuando veo la televisión me quedo dormido. Por este motivo me a la cama temprano.

Answer

Hi Craig, The answer is no, they are not interchangeable.

"Quedarse dormido" is "to fall asleep"
"Caerse de sueño" means "to be very sleepy" or "to be falling asleep" (in process)

First you "te caes de sueño" and then you "te quedas dormido".

Answer

Hi, yes, both have the same meaning. They are more like a native phrase I think. At least, here in Argentina we use both (not at the same time jaja).

Are they used interchangeably? Yes.

P.D.: Sorry about my bad english.