Help With Multiple Languages In Word 2016

[Gizmonster]

So I'm using Word 2016 to create a document in English and Spanish.
I want to add Spanish as one of the languages, so that when i type a new word in, it doesn't keep getting highlighted in red.
I've tried following the instructions that I've looked up, but that doesn't seem to work.
https://support.microsoft.com/en-us/topic/check-spelling-and-grammar-in-a-different-language-667ba67a-a202-42fd-8596-edc1fa320e00?ui=en-us&rs=en-us&ad=us

I don't know what I've done, but now all of my document has zillions of words highlighted in red. In some places it's English words that are highlighted and in other areas it's Spanish words.
I just want all of my document to recognise both English and Spanish words that are in the document.
Any input please??

[brainiac]

https://support.microsoft.com/en-us/office/turn-on-automatic-language-detection-194d309c-3e10-4bd5-a694-ba9bbdf4a28e

[Gizmonster]

I've followed those instructions. I have English (UK); English (US) and Spanish (Spain) in the "mark selected text as" list.
I also have the box checked "detect language automatically and I still have loads of words highlighted in red.

[calmck]

Do you have predictive text on

[Gizmonster]

I can't see any option for predictive text.

[Gizmonster]

It's really weird this.
I have a list of Spanish sentences and the English translation.
In some sections the Spanish words are highlighted in red and the English words are okay ...... and in some sections the Spanish words are okay and it's the English words that are highlighted.

[Jackdaw33]

Perhaps it can only deal with one language at a time. If your typing is to a high standard you can always switch the spellchecker off.

[chelle7272]

Look like others have the same oroblem with auto detect. A workaround here
https://answers.microsoft.com/en-us/msoffice/forum/all/detect-language-automatically-does-not-work/8a28d4a3-08a4-483b-816f-05737952a39d

[Gizmonster]

Still having problems with this and it seems like you can only spellcheck in another language if you highlight the text and select the language. I've Googled this extensively and there doesn't appear to be a simple workaround that will let me have a document in 2 languages and it will automatically spellcheck all of the document in both languages.
I'm must wondering if a different program (such as Libreoffice, or something similar) has this facility?