It's been a few years since I looked at verbal IQ data listed by ethnicity. It's important to look at recent data since so many immigrant groups have such small samples sizes, estimates are not very reliable. Using GSS data, here is the ranking of scores to a 10-point vocabulary quiz--a quick measure of verbal IQ. I omitted people not born in the US since the quiz is biased against non-native speakers:
Vocabulary Ranking by Ancestry
French Canadian 6.30
West Indies 6.19
American Indian 5.31
Puerto Rico 4.99
The pattern hasn't changed much since the last time I looked. What jumps out at me: 1) Mex-Ams and Puerto Ricans are still at the bottom, even lowers than blacks; 2) recent data indicates that American Muslims might assimilate better than European Muslims--the data here indicates that US Arabs are pretty smart; 3) Asian Indians (n = 40) still have a low average despite their reputation for intelligence; 4) it looks like southern Europeans don't do as well as northern Europeans (but Romania and Yugoslavia are high); and 5) central and Eastern Europeans might get a boost toward the top of the list by the large numbers of Jews (with a mean of 7.56) among their ranks.
And if you're thinking, this is just all environment, you're wrong: According to this meta-analysis, vocabulary is 62% genetic among children, and it is certainly higher than that among adults.
Oh, and if you think the differences are no biggy, again you're wrong: The gap between the top and the bottom is huge: well over 1 standard deviation.