I read that 'yo' is used to assert something e.g. おいしいよ. Can you not also end it in 'desu'? Are they interchangeable? Do they have completely different meanings, or is it simply a difference in formality/politeness and strength of emphasis/how strongly you are asserting something?
Edit: I know that desu is the polite form of da.
Edit: Added the question about whether the two are interchangeable.
Edit: I know that desu is the polite form of da.
Edit: Added the question about whether the two are interchangeable.