Sorry, my last entry was not shown in the best way; when I pressed "ENTER" the start of a new line was not taken over :-(
Now to your question: the conjugation of essen goes this way:
ich esse - I eat
du isst - (single) you eat
er/sie/es isst - he/she/it eats
wir essen - we eat
ihr esst - you (all) eat
sie essen - they eat
So you see: the word "isst" is used for the 2nd and 3rd person singular.
The subject of eating soup is interesting as some English people insist they drink soup. It does seem Germans do not drink soup although they may drink broth?
Suppe wird gegessen. Und von ungehobelten Personen geschlürft. Aber niemals getrunken. Obwohl Brühe tut man trinken!? Aber das ist ja dann keine Suppe.