Grammatical sentences assembled from a curated word bank, nonsense in meaning, correct in structure, which is exactly what a typing drill needs.
Every sentence here is built from a fixed grammatical frame (determiner, adjective, noun, verb, prepositional phrase) filled from a curated word bank. The result is always well-formed English and almost never means anything, which is the point. Chomsky made this famous with colourless green ideas sleep furiously: a sentence can be perfectly grammatical and semantically empty, and that gap is useful. For typing practice you want real word shapes and real sentence rhythm without content that distracts the typist into reading.
Latin filler is right when you need text nobody will read. Random English sentences are better when the words themselves matter to the test: checking how a font renders real English letter pairs and ascenders, testing a text-to-speech voice, sizing a component against genuine word lengths, or running a writing warm-up where the prompt should be parseable. The trade-off is that people do read English filler and will comment on it, which is exactly why lorem ipsum exists, so pick based on whether being read is a problem.
Because words are drawn at random into a fixed grammatical frame. The structure is correct and the meaning is accidental, which is what makes them useful as neutral filler.
Use it when the words matter, font rendering, speech testing, realistic word lengths. Use lorem ipsum when you need text nobody will be tempted to read.
The frame is a fixed length. Generate several and join them if you need a longer block of text.