有关The operator % is undefined for the argument type(s) int, String 的问题

一个javax.speech的小程序：

import javax.speech.Central;
import javax.speech.synthesis.*;  
public class TrySpeech {
    public static void main(String[] args) {
        Synthesizer synthesizer = Central.createSynthesizer(null);
        synthesizer.allocate();
        try {
            synthesizer.speak("Hello I am a computer", null);
            synthesizer.speak("Hello I am a <EMP>computer</EMP>", null);
            synthesizer.speak("Hello I am a <PROS PITCH=" + 10% ">computer</PROS>", null); //在这行报错
        } catch (Exception e) {
            e.printStackTrace();
        }    
    }   
}

在eclipse中敲完代码后报错：The operator % is undefined for the argument type(s) int, String

查过很多资料，类似错误案例很多，但与我这个代码的情况都不相同，不知道如何解决，求大神解惑

将出错代码行改为：

synthesizer.speak("Hello I am a <PROS PITCH=\"10%\">computer</PROS>", null);