Why is it that sometimes it will accept writing the single letter and also the whole name of the letter, but sometimes not? In this question, where it asked me to type what I heard, I put "δ δάδα" but it marked it wrong because it wanted "δελτα δάδα. In other questions, I can put either the single letter or the whole name of the letter written out and Duolingo will accept it as correct either way.
Agree with both of you. The problem arises when you only get audio which tells you "δελτα δάδα". It is impossible to know what you are supposed to type, δ or δελτα. Both would be correct, thus both should be accepted. On another note, I do agree it is smart to teach "δάδα" in this context. Maybe not the most used vocabulary, but my first guess was "dad" - good to know it's not.
If you're referring to "GTT Delta Mag Torch" which comes up after googling the phrase, from what I understand it's used to cut/melt glass.
But I have the feeling that the intention of this question was to practice with words that have one or more delta inside.
It's not a phrase a native Greek would use in everyday life.
What the?! This doesn't make sense! I typed "δ δάδα", but it actually wanted "δελτα δάδα"? What's the difference?!