There are fan-made translation patches. I would also recommend using the vsync patches, at least for Embodiment of Scarlet Devil, Perfect Cherry Blossom, and Imperishable Night, because they can have some input lag on some computers and the vsync patch fixes that:
https://thpatch.net/wiki/Touhou_Patch_Center
If you don’t have much experience with shmups/danmaku games, I would recommend starting out with either Perfect Cherry Blossom or Imperishable Night, or maybe Ten Desires, because they tend to be more forgiving and less difficult than the other games. I haven’t played Ten Desires, but of the other two, I would say I prefer the music and atmosphere of Imperishable Night, but Perfect Cherry Blossom is a bit easier to beat if you play on Normal mode or higher. If you want some more detailed comparisons:
Perfect Cherry Blossom
-There is a shield mechanic where if you collect enough cherry points (by collecting pink cherry blossom items or shooting enemies), you get a temporary shield. If you get hit or bomb with the shield active, you don’t lose a life (or bomb) and all the bullets get cleared off the screen. Once the shield expires or you get hit/bomb, your cherry points reset and you start collecting points to get a new one. It won’t help everywhere, but it can help escape tight spots without losing resources if you get a shield in the right place.
-Sakuya A is a really good beginner shot type: she has homing damage with decent power when focused and a wide spread that covers most of the screen when unfocused; and she gets four bombs per life (three is typical for the series, and sometimes you only get two).
Imperishable Night
-Touhou games have a deathbomb mechanic where you have a handful of frames after getting hit to press the bomb button, and if you are fast enough (and have a bomb in stock), you use the bomb and save yourself from losing a life. Typically the window to deathbomb is too short to wait until after you realize you’ve been hit to bomb, and you still have to anticipate that you will get hit to react fast enough, but IN is the one exception to this. IN has a unique bombing system where deathbombs cost two bombs instead of one, but in return you get a significantly bigger window to deathbomb. It is still a good idea to anticipate getting hit and bomb sooner rather than later, but you get noticeably more leeway in IN than in any other game.
-IN also has a great beginner shot type with the Border team (Reimu/Yukari). They have a slightly smaller hitbox than the other teams, have a slower movement speed which makes precision dodging a bit easier, and they also have homing damage with decent power. The one caveat with the homing is that if you focus, you have to start underneath the target so that your homing damage locks onto the target before it works.
-IN has spell practice mode. Normally you can practice any single stage after you have gotten through it in the game, but IN lets you practice any individual boss spell card that you have seen in the game by itself. This makes learning how to beat spell cards much easier.
-If you want to ease into the games as gently as possible, IN has by far the easiest easy mode of any game in the series.
Ten Desires
I haven’t actually played Ten Desires, so I don’t know that much about its gameplay, but it has a reputation for being one of the easier ones. You get a chargeable trance mode that makes you invincible for several seconds and greatly increases your power, so you can essentially skip difficult sections of the game if you plan your trance mode usage. It takes a while to charge, though, so you have to pick and choose when to use it. This game also has spell practice mode. The game (and in general any game from Mountain of Faith onward) is more visually polished than the earlier games. One downside is that collecting extra lives is more complicated in this game than in PCB or IN, so until you learn what you are doing, you might end up with fewer resources.
Other games
Some people think Mountain of Faith is actually the easiest game in the series, but that is because you can stock up and use a ton of bombs. Learning how to use your bombs properly is actually a fairly difficult skill, so the game’s difficulty being tied to how well you can use your bombs isn’t necessarily the most beginner friendly. If you’re using all your bombs in other games but finding you just don’t have enough resources to get through the game, you might give MoF a try.
Subterranean Animism is a lot of people’s favourite, but it is also one of the hardest games. If you are already familiar with shmups or arcade difficulty, SA might be more your thing.
Trace will probably suggest Embodiment of Scarlet Devil since it’s the first Windows game and there’s something to be said for starting at the beginning, especially if you eventually plan to work your way through the whole series. It definitely has the least polish of any game in the Windows era of the series, though.
If you prefer other types of games, there are fan-games in virtually every genre, but they tend to be on the difficult side. My personal favourites are Fantasy Explorer Nitroid (an exploration Metroidvania style puzzle platformer) and Marisa and Alice’s Trap Tower (a puzzle platformer), both by a group called Desunoya. They both get really demanding toward the end, especially in the “extra” stages, but the earlier stages aren’t that bad.