Sword design and fighting style* are absolutely connected to the environment that spawned them.
Environment, as in, landscape, terrain, waterways, shoreline and seascape, natural resources, geographic placement, weather etc .... all play into the style of an art.
- What kinds of weapons are available - Locally made (with naturally occurring metal ores and techniques), or only imported, and whether they are common or rare.
- What type of protective gear is worn - Climate dependent (hot/cold) and on materials availability.
- Where fighting happens, and thus what weapons are appropriate - Open terrain/jungle/rice paddies/forest/city streets.
The enemy also plays it's part
- Who are they and why do they fight?
Is it about
- Resources? (Piracy/Bandits)
- Cultural Differences/Status/Politics?
- Are the enemy locals? Outsiders? Foreigners?
- Physically bigger/smaller/stronger? Technologically more advanced?
- How many have come in relation to you?
Cultural aspects ...
- Is this a blade carrying culture?
- Is there a strong tradition of Honor? Personal/Family/Tribe?
- Are there class restrictions about who is allowed to own and carry certain weapons?
- Taboos and rituals associated with fighting?
- Previous enemies?
- Recurring threat?
- Separate fighting elite, or everyone pitching in.
- Group fighting strategies, or individuals for themselves?
- Guerrilla style/Raid/Battlefield
Everything plays a part, down to whether or not people had horses or wore sandals.
Of course not having actually been part of a culture, or alive in history, means that extrapolating from a sword design or way of moving to understand an art, is always guessing ... and obviously nothing is ever truly certain. But remembering that pragmatic folks with real problems to solve, and crises to overcome, designed the tools, and lived in the societies and the environments that they fought in, means you can make some good guesses about the parameters of reasonableness within a style, and gives you some great insights in why things are as they are, and thus how one style looks in relation to another.
There is usually a rational chain of thought that can be traced back through knowledge .... and this rationality is the clue how things ended up as they did. Conversely, losing the rationality for something, leads to the greater and greater potential for errors.
In the end it is no big surprise that there are commonalities between sword fighting systems from around the world (Human brain, 2 arms 2 legs, squishy bits and bony bits etc), but it is also no surprise how each is different from the others, and has a particular flavor because of the context, the environment, that it grew up in.
Understand the context, and all becomes much simpler to unravel .....
(* - Note: we are talking style and design here .... not the method of passing knowledge forward.)