Invalid Language: 'fil' on 'hreflang'

Question

I'm trying to translate a website made with Laminas for Philippines in Filipino language and inform the search engines of this via the rel="alternate" and hreflang="fil" tags.

However, using several tools online to check if this is "ok" they will all say the same thing:

Invalid Language: fil

According to Wikipedia this is correct (or maybe I`m looking at the wrong place?).

On my website I want to use only generalised language codes, so for example I don't want to use "en-PH".

Tools I have used:

• https://dejanmarketing.com/flang/
• https://technicalseo.com/tools/hreflang/

To be honest I have tried several combinations like "ph", "phl", etc; but none of them are correct.

What might be the issue and why "fil" is incorrect language code for Philippines?

Answer 1

if still relevant - hreflang="fl"