1、AVSpeechSynthesizer文本到语音

使用方法

 _synthesizer = [[AVSpeechSynthesizer alloc] init];
 _voices = [@[[AVSpeechSynthesisVoice voiceWithLanguage:@"en-US"],[AVSpeechSynthesisVoice voiceWithLanguage:@"en-GB"]] mutableCopy];
 _speechStrings = [@[@"Hello AV Foundation. How are you?",
                        @"I'm well! Thanks for asking.",
                        @"Are you excited about the book?",
                        @"Very! I have always felt so misunderstood",
                        @"What's your favorite feature?",
                        @"Oh, they're all my babies, I couldn't possibly choose.",
                        @"It was great to speak with you",
                        @"The pleasure was all mine! Have fun!"] mutableCopy];

- (void)begainConversation{
    for (NSUInteger i = 0; i < self.speechStrings.count; i++) {
        AVSpeechUtterance *utterance = [AVSpeechUtterance speechUtteranceWithString:self.speechStrings[i]];
        utterance.voice = self.voices[i % 2];
        utterance.rate = 0.4f;
        utterance.pitchMultiplier = 1.0f;
        utterance.postUtteranceDelay = 0.1f;
        [self.synthesizer speakUtterance:utterance];
    }
}

AVSpeechUtterance属性介绍

+ (instancetype)speechUtteranceWithString:(NSString *)string;
创建AVSpeechUtterance实例，传递字符串到speechUtteranceWithString初始化器

rate 语音播放速率，数值介于AVSpeechUtteranceMinimumSpeechRate与AVSpeechUtteranceMaximumSpeechRate之间，这两个字分别是0.0、1.0，默认是AVSpeechUtteranceDefaultSpeechRate值为0.5

pitchMultiplier 设置声音音调，值一般介于0.5(低音调) 和 2.0(高音调)之间，默认为1.0            //  [0.5 - 2] Default = 1

volume 音量，         //  [0-1] Default = 1

postUtteranceDelay 播放下一段语音有短暂的停留，默认为0.0，可以类似的设置preUtteranceDelay的值

voice AVSpeechSynthesisVoice类型，设置语音

支持的常用语言列表

• zh-HK
• zh-CN
• ko-KR
• en-GB
• en-ZA
• en-AU
• en-US
• en-IE