Present participle; Past participle - tittering - tittered Present - titter - titter - titters - titter - titter - titter Past - tittered - tittered - tittered - tittered - tittered - tittered Future - will titter - will titter - will titter - will titter - will titter - will titter Present conditional - would titter - would titter - would titter - would titter - would titter - would titter Present Perfect - have tittered - have tittered - has tittered - have tittered - have tittered - have tittered Past Perfect - had tittered - had tittered - had tittered - had tittered - had tittered - had tittered Future Perfect - will have tittered - will have tittered - will have tittered - will have tittered - will have tittered - will have tittered Past conditional - would have tittered - would have tittered - would have tittered - would have tittered - would have tittered - would have tittered Imperative - - - titter - - - - - - - -