Sadly the topic of lactose intolerance is rife with misinfo, biases, and dogwhistles, hence my rapid-fire questions in the previous comment. Most commercial yogurt products sold in grocery stores today are heavily laden with sugar and so mildly fermented that their probiotic quanlities are nearly nullified. Commercial unflavoured kefir is slightly better, but the overall probiotic effect is still questionable since we don't have affirmative answers on how much of the microbes can survive through our stomach acid, or how much of them can establish in our guts vs. heading straight for the exit like passengers on a roller coaster.

As for the spelling of yoghurt there's no correct version honestly, they are all transliterations of the same Turkish word https://en.wikipedia.org/wiki/Yogurt#Etymology_and_spelling