What are the potential drawbacks of converting an untyped language like PHP into a typed language?

Converting an untyped language like PHP into a typed language can add complexity to the codebase, increase development time, and require additional effort to maintain type annotations. However, the benefits of type safety and improved code quality may outweigh these drawbacks in the long run.

// Example of adding type annotations in PHP
function add(int $a, int $b): int {
    return $a + $b;
}