PHP: This has been a language I have known about and used for almost 20 years, but I only just recently learned to code with it fully, I have completed 3 full courses on it and 10+ other supplementary courses. I am still learning more about it day by day and plan to use it continually for web projects even though it's not the hottest thing in coding trend wise. While learning JS and Python as a side effect I have gotten better with PHP.
HTML/CSS: Since I like Web Development I am constantly learning new things about both, CSS is very deep and can do amazing things. Really getting the basics of both are the start, then learning how to start a project with an organized structure is key to both of these. There are 'WEB' rules to creating a 'proper' layout for any website, accessibility features that most do not even think about (myself included but I will improve here), then something I personally do not prioritize and that is SEO or search engine optimization, but can if need to.
MYSQL/MariaDB: Database stuff is crucial for a back end web programmer, my training has been very basic on the SQL syntax and its not very hard. I have lots of years of practice administering and running sql commands to alter data on many websites I have managed over the years. Recently I have learned some of its expanded programming like abilities like INNER JOIN and so on. When learning database manipulation security and handling data is a huge deal, like in PHP it has made the learning progress much longer due to all the added precautions you must make in your code 'msqli vs pdo .etc'. I really need to work more on this, but its a must have for me.
Python: I just started Python lessons, I wasn't gonna start it till down the road but then I just could not ignore all the basic simple tasks it can help with. They say it's the easiest high level programming language to learn, and I def agree. It has features in its syntax that are just so damn smart, I keep learning things and if you can think of it Python can do it. What really excites me is Web + Machine Learning, that sold it for me and started it now. I have no clue how to even setup a web app in it currently using a framework like Django or Flask but I will begin those lessons in a few more weeks to put up some simple input chat box web app with some 'basic' algorithm to respond.
Is it a mistake for me learning six things + frameworks + libraries at the same times? I think it might effect things, but what I am noticing is my threshold for learning is increasing each month. Learn one language decently and the rest are a 'tad' easier.