Many of my current students come to me directly from other teachers who actually discourage any type of tongue articulation whatsoever. I won't criticize this approach, but my opinion differs entirely and I feel that it can be debilitating in some cases. Many of these very students have a great deal of difficulty in playing certain passages which require more defined attacks. So I feel that instructing them to eliminate ANY approach is wrong and limits their ability to execute specific articulation requirements. Long story short, I feel that it's a teacher's job to present a variety of materials to students and then allow them to process the information and make good use of the material while in development of their individual voice. I don't consider it to be my job to force them to comply with my ideas of what's right and wrong--and by that I mean telling them NOT to address things which may be necessary for them to master in order to be a contender in this competitive world of music performance.
So, to any student that has articulation problems, please make a point to inquire to your teacher about specialized tonguing and finger coordination exercises which will help your timing, attacks, breath control, evenness and phrase definition. Every teacher has their methods and if you feel that your progress is slow or if you don't find their direction and instruction to be very helpful, don't hesitate to go elsewhere for other opinions from players that you respect. No one knows everything and if your teacher were a doctor and you weren't satisfied with their diagnosis, you'd probably want a second opinion as well.