Well, there is no word "tumblr", but there is "tumbler". Yes, you can pronounce it "tum-blur", or if you are British it is probably "tum-bluh".

I say tumbler.

You should study phonics! The word is Tumbler, not tumblr You say Tum as in the start of tummy and then bler..imagine you are going bleeeerrrrr/, like the sound you would make if something didnt taste nice!

Its the name of a web site.

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