Don't know much hiragana from katakana, but I had lots of fun struggling through this game.
There's not a lot I can tell you about the story. You start out being born before the classic Dragon Quest (or warrior as it were) theme plays out, then you will find yourself on a boat with your father on a trip to the mainland. Soon enough you will meet another character, a girl, and the quest begins.
There really isn't much more I can tell you about the story without spoiling things, since while I couldn't read much of it, the parts I understood seemed clear and conclusive.
The combat is standard Dragon Quest fare. Enemies stand in static poses while you decide your moves, then exchange blows before starting over on your next turn. You can capture and train some of the enemies, which will then join you in battles along with other companions you meet along the way.
As with other Dragon Quest games, you save at save points, buy and sell at shops, everything you've seen before you will see again. This isn't to say it's dull or boring, but if you are looking for revolutionary you may want to look elsewhere.
There is plenty to like about this game, enough in fact that I was able to complete it once without understanding a whole lot of what was happening, and scribbling things down to use a book to translate as I played, such as spell names, towns, and sometimes weapons.
I understand there are translated versions available out there, so it will be worth looking for if you get the chance. It's a great game in the series, and totally worth your time as long as you are a traditional role player in search of old school role playing. It was spankin' new and imported when I played it, so by now many dozens of classic style role playing games have since been released, including the brutally long Dragon Warrior 7 and the epic and brilliant Dragon Quest 8.
At any rate, this was a fun experience, and it was an experience worth having.