Re: Can one take another martial art while taking Aikido?
As a long time budo-hobo, so to speak, I'll toss in my 2 cents and wander away perfectly content with whatever folk want to think. Me, I did a lot of stuff over the years. Twas all cool. I did find when I was newer that I had problems with, well, let's call it conceptual interference among varied arts. The way I like to look at it is that most mature arts have a sort of underlying "operating system". And if you're trying to program yourself in both environments at the same time what works in A might be anathema to what works in B. And in the end trying to do both at the same time when you don't have a solid understanding of the underlying OS similarities and differences is really not a great idea. "Jack of all trades, master of none" comes to mind.
That said, once you've got the time in, once you've managed to get some degree of mastery of one, the other arts seems to be easier to grasp, at least IMHO. The contrasts are brightly visible while the similarities often seem obvious. So at that level I find that if anything doing more than one art can be helpful to both. But... It does require some degree of master prior to prevent the sort of cognitive collisions that inevitably occur.
So my answer is... It depends. In my experience I found it eventually enriched my understandings of all the arts including the deficiencies and limitations. But I gained a greater appreciation of each art's strengths as well.
No, I wouldn't recommend doing 2 arts at once as a beginner. And there's always the danger of nikyu shihan disorder among those who move from one to the next to the next. In other words, figuring out whether you have some degree of mastery in an art is itself a tricky thing indeed.
So... Yeah, yes and no. Sure, go for both and no, focus on one. There, how's that work?
Shades of grey and all that jazz.