The answer to whether parrots can really speak is one of those complicated responses where the most accurate answer is yes, no, and sort of.
Yes, parrots can really say words. A pet parrot can be trained to say phrases like “Polly wants a cracker,” or “pretty bird.” Parrots are also commonly known to sing fire alarms or learn phone ringtones.
This is called mimicry. Parrots do it because they enjoy singing and they are social birds. To build a bond with you, your bird will “talk” with you.
As to whether or not they can understand what you are saying, the answer is sort of. This is a topic of intense debate among bird owners and scientists alike. One standard line of thinking is that while they don’t necessarily understand the phrases they are saying in a literal sense, they do associate the phrase with a specific situation. So they know “Polly wants a cracker” is stated at the same time food happens, but they don’t know which sounds mean what.
If you are wondering if you can have a full conversation with your parrot, the answer, unfortunately, is no; that is very unlikely unless you want that conversation to be very brief. The African Grey parrot has been known to learn a massive 1,000 words in total. Be aware, however, that every parrot is different. One bird may learn a thousand words, another may learn ten, and another may never speak at all. The personality of your parrot will affect how chatty they decide to be, as will how well they are trained early on.