In {HEAD ~ the case} of obtaining {TAIL ~ the street number}, voice recognition is tried first before operator involvement is used 
of obtaining
In { HEAD ~ the case } of obtaining { TAIL ~ the street number } , voice recognition is tried first before operator involvement is used
OTH HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH