Those combinations are phonemes, nothing more. Addendum: The letters 'i' and 'j' look distinct (though very close) to me in that image. At first I thought it w

Those combinations are phonemes, nothing more. Addendum: The letters 'i' and 'j' look distinct (though very close) to me in that image. At first I thought it was just weird 'kerning', but the caption seems to say it's a single glyph. That doesn't need to mean it's a single letter though; it can merely be a ligature. Upon further reflection, I'm not sure I understand what you mean by being thought to write them as a single letter. I was only thought cursive in school and I'm not sure what difference it would make to write them as one or two letters in cursive.