Ground floor · your voice
Two vowels meeting, with nothing between them. English refuses to leave that gap open, so it grows a small w or y to bridge it — and if you stop instead, the sentence breaks in half.
Go on.
This browser cannot record. You can still hear the line and read how it works, but the check needs a browser with microphone recording.
A diphthong is already a slide between two vowel positions. Linking is that same movement continuing into the next word, which is why these two things are one skill and not two.