public Builder setDisplayLanguageCode(java.lang.String value) {
      if (value == null) {
        throw new NullPointerException();
      }
      displayLanguageCode_ = value;
      bitField0_ |= 0x00000002;
      onChanged();
      return this;
    }
<pre>
Optional. The language to use to return localized, human readable names
of supported languages. If missing, then display names are not returned
in a response.
</pre>

<code>string display_language_code = 1 [(.google.api.field_behavior) = OPTIONAL];</code>

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