You can use asti(singular)/santi(plural) (both stem from *h₁es- the proto-Indo-European verb) and bhavati (to become).
There is no 'The'in Sanskrit.
There are 45 words in "welcome" if you count all of the following: Words that start with capitol letters are names. Words that are in ALL CAPS are abbreviations . (Welcome is included.) Moe Mel MC...
karyakrama
ringmingleprimsewglowcomesingmownowgrimewinwineminemeseegreenwegincrewrowweregrewwringwinglimenot to mention all the plurals you could do with the "s"