TS Error for SpeechGrammarList, but this is part of the Web Speech API, and the interface is implemented in "DOM". Why is TS still giving this error?

Code:

export interface SpeechRecognitionProperties {
    grammars?: SpeechGrammarList; //TS2304: Cannot find name 'SpeechGrammarList'.
    lang?: string;
}

"typescript": "^4.4.4"

tsconfig:

{
  "compilerOptions": {
    "target": "ESNext",
    "useDefineForClassFields": true,
    "lib": ["DOM", "DOM.Iterable", "ESNext"],
    "allowJs": false,
    "skipLibCheck": false,
    "esModuleInterop": false,
    "allowSyntheticDefaultImports": true,
    "strict": true,
    "forceConsistentCasingInFileNames": true,
    "module": "ESNext",
    "moduleResolution": "Node",
    "resolveJsonModule": true,
    "isolatedModules": true,
    "noEmit": true,
    "jsx": "react-jsx"
  },
  "include": ["./src"]
}