Natural Language Speech Recognition (NLSR) allows you to create a more natural, conversational style of interacting with the Avaya IR system. Depending on the external vendor's speech recognition engine and its capabilities, you may not need any other speech recognition technologies in your system.
There may, however, be times when it is more advantageous to use a variety of speech recognition technologies, depending on what kind of speech you need to recognize at each prompt. NLSR can be used in combination with other recognition technologies such as WholeWord.
If, for example, you are looking for a simple "yes" or "no" response from a caller, it may be more efficient to use WholeWord speech recognition rather than tying up your NLSR resources.
In the end, however, a great deal depends on your NLSR engine and its capabilities, when trying to answer the question of whether to use other speech recognition technologies in conjunction with NLSR.