At first I thought my hearing was going bad when I kept hearing すいません(suimasen) even in beginner lessons. But after several passes and checking around other sources, I found that you can say either すみません(sumimasen) or すいません(suimasen).
From what I've reasoned on various posts elsewhere on the net, the latter appears to be slang. Could we get clarification on the usage? I think this should appear in a public lesson as I would hate to offend someone with informal usage of this phrase. A response here would be great too!
Thanks,
George