Cannot read property '_intl' of undefined

I use mat-paginator from Angular(Material) 12, which helps me implement the pagination feature. Besides pagination, I also would like to customize the label in the pagination from "Items per page" to "Foo per page"

My first implementation is following

export class MyComponent implements OnInit {
  @ViewChild(MatPaginator) paginator!: MatPaginator;

  ngOnInit() {
    this.paginator._intl.itemsPerPageLabel = 'Foo per page';
  }
}

This one does not work and it shows the error

ERROR TypeError: Cannot read property '_intl' of undefined

I made the second try with the following implementation

export class MyComponent implements OnInit {
  @ViewChild(MatPaginator, {static: true}) paginator!: MatPaginator;

  ngOnInit() {
    this.paginator._intl.itemsPerPageLabel = 'Foo per page';
  }
}

Then it works like a charm!

Why do I need to set {static: true} for @ViewChild to make it work?