Perhaps you should try some spelling variations:
oral communication » personal communication
developpements en » developpement en, developpement et, developpements de
variation ban » variation bei, variation a, variation von
de variation » der variation, die variation, does variation
apologie de » apologie des, apologia de, apologien der
does oral » does formal, does oil
ban does » behn does, plan does, far does
a bet » a best, a bent, a beta
a et » a set, a net, a jet

You may be able to get more results by adjusting your search query.

• If you are trying to use Boolean operators, they must be ALL CAPS: apologie de variation ban does oral communication ((a et) OR (a bet)) developpements en afrique.~.
• Adding a wildcard symbol may retrieve word variants: apologie de variation ban does oral communication ((a et) or (a bet)) developpements en afrique.*.