Need Advice – One website with "bilingual" (Spanish/English) languages

I need some accessibility and usability advice for a website. I am a designer volunteering for a non-profit and is my team (product manager and three developers).

I am working on a site where my product manager and client wants the site to be "bilingual"(Spanish/English) using ONE site, not two separate sites. The reason for making one site is due to timing and features prioritization. Our developers are learning how to code in Wordpress.

I suggested doing one language first, Spanish. Our target audience is 80% Spanish speakers. The other target audience is English speakers. I voiced my concerns about the two languages taking up real estate. Plus, I have some concerns with scannability of the website. Not all the website is bilingual, some pages are and some pages are not. It's a small website.

  • Have anyone come across this issue?
  • Do you have any recommendations or articles to make an inform decisions?

It's three pages:

  • Homepage - Bilingual
  • About - English
  • Upload - Bilingual
  • Nav - I want to be one language.
  • Login - Bilingual

Thank you!