Does the text-to-speech demo on gcp work for SSML?

Question

I have been trying out the google cloud gui demo . I want to use native pronounciation of a word from an english speaker.
For example -

<speak>The french word for cat is <lang xml:lang="fr-FR">chat</lang></speak>

Unfortunately , the french pronounciation is not correct when i use an english speaker and vice-versa. This is an example from google-cloud tts documentation only . Am I missing something here or are <voice> and <lang> ssml tags not accessible in the demo , since rest of the tags like <break> , <emphasis> etc seem to work .

Here is the json of the above query -

{
  "audioConfig": {
    "audioEncoding": "LINEAR16",
    "effectsProfileId": [
      "small-bluetooth-speaker-class-device"
    ],
    "pitch": 0,
    "speakingRate": 1
  },
  "input": {
    "ssml": "<speak>The french word for cat is chat</speak>"
  },
  "voice": {
    "languageCode": "en-US",
    "name": "en-US-Neural2-A"
  }
}

in the ssml field clearly the lang tag is not reflected.