public Builder setDetectedLanguageCodeBytes(com.google.protobuf.ByteString value) {
      if (value == null) {
        throw new NullPointerException();
      }
      checkByteStringIsUtf8(value);
      detectedLanguageCode_ = value;
      bitField0_ |= 0x00000004;
      onChanged();
      return this;
    }
<pre>
The BCP-47 language code of source text in the initial request, detected
automatically, if no source language was passed within the initial
request. If the source language was passed, auto-detection of the language
does not occur and this field is empty.
</pre>

<code>string detected_language_code = 4;</code>

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