The 1st act of Contract had virtually no words.( I think about 10 at the end) The 2nd act in the restaurant had quite a bit of speaking and the 3rd act ( Girl in the Yellow Dress) was a full script esp moving to the "bar" from the Apt.
There was a ballet sequence in "High Button Shoes" using Keystone Kops that has no words that Stroman referenced in a Ballet tribute to Robbins .
I guess that a play w/out words would just be mime and I can't think of a play that is totally mimed.
Robert Wilson's "Deafman Glance" comes to mind. I don't know if it was entirely without words but certainly significant portions are, including the hour-long scene with the black woman in Victorian garb very slowly giving her children milk before stabbing them. I think a silent play is an interesting idea, either with sign language or being about something that's impactful but doesn't require words, like Akerman's film Jeann Dielmann. I think "Small Mouth Sounds" was also done with limited verbage.