Learn Italian: Non è uno sbaglio. - It is not a mistake.

Masculine words usually take the article un (like un cane). But when a masculine word starts with an "s" followed by another consonant (here, the "sb" in sbaglio), you must use uno. This is because saying "un sbaglio" creates a harsh traffic jam of consonants, so Italian adds the "o" to make it flow smoothly out loud.

Where is the word for "it" in this sentence?

Italian usually drops subject pronouns (like I, you, he, or it) because the verb itself gives enough information. Here, è is the "is" form of the verb essere (to be). The "it" is simply understood from the context without needing a separate word.

How does negation work with non è?

To make a sentence negative in Italian, you just put non immediately before the verb. Since è means "it is", placing non directly in front gives you non è, meaning "it is not".

How do I pronounce the gli in sbaglio?

The gli makes a special sound that is similar to the "lli" in the English word "million". You make it by pressing the flat, middle part of your tongue against the roof of your mouth. It is never pronounced like the English word "glee"!