public Builder setSourceLanguageCode(java.lang.String value) {
      if (value == null) {
        throw new NullPointerException();
      }
      sourceLanguageCode_ = value;
      bitField0_ |= 0x00000002;
      onChanged();
      return this;
    }
<pre>
Required. Source language code.
</pre>

<code>string source_language_code = 2 [(.google.api.field_behavior) = REQUIRED];</code>

@param value The sourceLanguageCode to set.
@return This builder for chaining.
java-translate/proto-google-cloud-translate-v3beta1/src/main/java/com/google/cloud/translate/v3beta1/BatchTranslateTextRequest.java