I wrote 'would you be able to come with me? and it was rejected. Apart from the hover hints which can often be very misleading, the verb 'poder' means 'to be able' so I don't at all understand why my sentence is rejected. I'm going to report it - not that it will do any good.
and even the "hint" says "WOULD (you) be able to..." for podria, not "COULD (you) be able to..." so why would "Would you be able to come with me" not be correct? And therefore why would just "would you come with me" not be correct either? ( even DL leaves out the "...be able to..." in their answer....)
Totally agree. Poder indicates ability ("be able").
"could you come with me?" is simply "vendría (usted) conmigo?"
There's a sense in which "Podría venir conmigo" is redundant, if you are translating the conditional as "would" (condition met), since "poder" also includes ability and condition met.
Unless.... you take the "should" sense of the conditional.
"Should you be able to come with me?"
"You" is in the verb "podrías" which is the conditional tense of poder for "tú" .
Poder means to be able to, and it is an irregular verb.
Present tense: I am able to, you are able to, he is able to...
Yo puedo, tú puedes, ud./él/ella puede, nosotros podemos, uds./ellos/ellas pueden.
Conditional tense: I would be able to, you would be able to, he would be able to...
Yo podría, tú podrías, ud./él/ella podría, nosotros podríamos, uds./ellos/ellas podrían.
Full conjugation of poder: http://www.spanishdict.com/translate/poder#conjugation
Conditional tense in Spanish: http://www.spanishdict.com/topics/show/97
I think that would be "Can you come with me?". The conditional mood is inferred when the English translation includes "could/would/may have, etc.", words of probability/possibility.
Also, "podría" should be able to be used with the subjects "I/you/he/she".
Not stupid, but easy to find out by using a Spanish verb conjugation website. I like this one:
Keeping in mind that poder is an irregular verb,
podria, podrias = conditional (could you come with me),
podia, podias = imperfect (were you able to come with me),
podrá, podrás = future (will you be able to come with me},
va/vas a poder = phrasal future (Are you going to be able to come with me)
Podria also means "could he" "could she" "could you" (formal). It helps to consult a verb conjugation table for questions like this. It also helps to read through the discussion. Your question has been answered more than once. And yes, it is a perfectly good, and rather common, sentence.