I've been giving English conversation lessons to a theology professor for about a year now. He's getting on in the years - a couple years from retirement - and his primary goal has been just to get his spoken English going stronger. In particular, he'd like to make his presentations at conferences more free-flowing and to be able to make small (medium and large) talk afterwards. His mother tongue is French but he's been teaching at a German language university for many years.
I'd like to add some more specific inputs to our lessons but I can't seem to find the right material. His passive skills are excellent - he reads widely and with perfect comprehension in his field - and he can communicate quite understandably, though slowly, with typical errors and a heavy accent (that's actually kind of cute). He is a linguistics specialist and can grasp any concept about the language faster than I can even say what it is. I brought along Cambridge Advanced Grammar in Use and he could plow through a chapter in five minutes with perfect conceptual comprehension.
However, he also continues to make very simple errors - for example, he has trouble choosing between present simple and continuous or often uses the present tense for past events. Sentence order tends to get wander hither and yon while definite and indefinite articles come and go with the tide. (Prepositions are a problem too, but I won't beat him to hard there - prepositions are difficult in any new language.) In many cases his mistakes are typical of French or German speech patterns.
One other limitation is that he enjoys the weekly lessons (a good hour), but doesn't have much time to study in between.
Right now we spend about 15 minutes reading a chapter from Advanced Grammar in Use and about 45 minutes talking about just about anything under the sun, while I take notes and show him problems under the categories Pronunciation/Articles & Prespositions/Word Order/Other Grammar/Vocabulary/Idioms. However, I don't think the work book is a good choice - particularly since he doesn't do the homework - and it seems like he isn't making very good progress with his typical problem patterns - though he greets them like old friends when I point them out.
Any tips here?