My favorite words to say in various languages:  Esperanto:  insekoj, Portuguese:  liquidificador, German:  Flammenwerfer.  I'm not sure I have a favorite Spanish or English word.  Maybe the longest one for English:  antidisestablishmentarianism.  I'll have to think about Spanish.
@hobbsc  my favourite Portuguese word could be #metralhadora. The word looks nice to me. Too bad it translates as machine gun, so it just cannot be a favourite word.
@mcscx2 well, flamethrower is a violent word. Those are all just fun to say.
@hobbsc  the German for 5 amuses me as it sounds like a bag of flour hitting the floor. 
@luke i will never say 5 the same again...
@hobbsc my favorite english word is 'widdershins'
@jezra you kiss your mother with that mouth?
@jezra i'm adding that one to my vocabulary, thanks.  really going to confuse my son.
@jezra great word! I forget if it means "clockwise" or "anti-clockwise", though. IIRC there's a related word "deosil".
@ericxdu23 deosil relates to the path of the Sun and will result in a sun dial moving clockwise.