Speech is the correct spelling of the word that means to give a talk in public and a way in which humans communicate. Speach is incorrect and should not be used in English.
“Speech” has two meanings in English.
The first meaning has to do with the way humans talk to each other. “Speech” is the name for human vocal communication with language.
Speech is a uniquely human ability.
“Speech” also means to give a presentation at an event, usually like a wedding or some sort of celebration.
The best man gave a hilarious speech at the wedding.
“Speach” is incorrect and should not be used in English. Many people think that the spelling of “speech” is “speach” probably because “peach” sounds very similar to the “peech” in “speech”.