Splitting a string in bash on something specific -

i had string cut based on colon. have string in format of: mon date, year birthday (input)

what can can have: mon date, year without birthday? (or in other words desired output of:)

mon date, year 

clarification: birthday in case literally string "birthday"

i know various posts on website tell how split strings based on delimiters, have no idea how split string based on specific word/string , couldn't find on here

with bash

orig="mon date, year birthday" val="${orig%% birthday}"  echo $val mon date, year 

it's not splitting here, it's rather "stripping" off fix suffix. bash has built-in.