Single-class　support　vector　machines(SC-SVMs)　are　different　from　the　standard　two-class　SVM　techniques.　This　algorithm　is　used　to　allow　the　pass　through　of　the　only　positive　data　by　treating　the　origin　as　the　only　member　of　the　second　class.　Here,　we　present　an　algorithm　for　rejecting　out-of-vocabulary　(OOV)　phrases.　Our　method　uses　SC-SVM　mechanism　to　detect　and　reject　the　phrases　of　OOV.　We　also　depict　the　trends　in　in-vocabulary(IV)　correct　recognition　and　OOV　rejection　with　the　number　of　command　increasing　and　give　an　analysis.