I know what you are saying. It often seems to be that in speaking practice, the students provide mostly answers. To redress this balance, you could try some of the following activities:
1) Use questionnaires: you can design these yourself or have students write them together in class. You can practise general questions such as name, age, address etc. This would be better at the beginning of the course before they know each other too well.
The questionnaire could also focus on a specific question form, eg how often do you ....? or when did you last ......?
After writing the questionnaire (or studying it briefly if the teacher prepared it), students can mingle and ask the questions.
2) Have a 3 or 5 minute activity built into each class. One student is 'the teacher' for this period of time and asks students questions. The role of teacher can rotate. You can use this is a filler at the end of a lesson.
3) After a reading activity, put the students in groups. Each group prepares questions about the text for their classmates. Students then pair up with someone from another group. They ask and answer each other's questions.
4) Do a 'find somebody who ...' activity. Before class, you need to prepare a list of sentences such as
Find somebody who ...
has been to India
Students then mingle and ask their questions - they will need to reformulate them into: have you been to India? etc. They ask the quetion to everybody in the class until they find an affirmative answer. They then write the name of this person next to the question. The advantage of this exercise is that they repeat the question which reinforces it in their minds.