This paper is focussed to the introduction and use of Speech Processing Techniques in the Assesment of the Speech Trace, with applications in Computer-Aided Language Learning (CALL). The general structure of a CALL Environment, and a Speech Interface to allow the spoken interaction of the student are presented. The system is intended to exploit and improve the speaking abilities of the student through a progressive Listening & Comprehension process supported by the registering and evaluation of the student's Speech in terms of Phonetics and Prosody. The general premises for a successful application of these techniques in Language Learning Laboratories are also presented.