Honestly, I think your DD has a better chance of learning to converse with her grandmother by actually doing just that.
I completely agree.
OP, I grew up in San Jose CA, and it was handy to know Spanish. So that's what I took. Some other friends took French and Spanish (all of my friends and I started our languages in 8th grade). Today, we all use our languages to about the same extent as each other, it seems. Those of us who made fun of the French and German kids use our Spanish just as much as they use their languages. And Spanish is easy enough to pick up, if you find yourself in need of knowing the basics.
Several of my friends were from some sort of Spanish-speaking families...Mexican, Cuban, etc. Some of them took Spanish, thinking it would either be easy for them OR that it would help them at home. NONE of them found either of those to be true!
Why? Because the Spanish spoken by relatives was NOT textbook Spanish! Each family from each different area spoke it differently. One friend had a mom and grandma who spoke mainly Spanish to each other. But she ended up finding out that they had totally morphed their Spanish into Spanglish. Just like my husband's family, including their Korean-born mom, speaks "Konglish". So it made her feel funny about her relatives...for instance, "to rent" is actually alquilar, if memory serves. MOm and grandma would use the made-up verb "rentar".
She survived it, because she is IMMENSELY intelligent to begin with. Others weren't so lucky, it really mixed them up.
The Cuban-American friend really only survived the class because her mom, the caucasian-american parent, was a Spanish teacher herself! So her mom was able to help her, because the Spanish spoken in her home was not anything like what was being taught in the textbook.
So OP don't be upset by this choice. Learning Spanish in a classroom isn't really all that likely to help her with what her grandmother probably speaks. If she's interested in talking with her grandmother, she will do so. If not, a class isn't going to make her do it.
Aren't both languages similar? I have heard once you learn one it is pretty easy to pick up the other.
I think that once you take a language for a couple years and really put an effort into it, it becomes easier to pick up most languages.
I actually find a lot of similarities between Spanish (took it from 8th through 11th grade) and Japanese (12th grade and freshman year of college). Having the Spanish really helped me with Japanese.
This is kind of off topic - but do students in the US generally not take a second language before high school?
Generally speaking, that is correct. Ridiculous, isn't it?