The language might not be the biggest problem. The insane amount of regulation we have might be. Besides regulation, there are plenty of other differences between countries within the EU.
For example, we don't have a unified banking system in the EU. Each country has its own preferred method of payment. In the Netherlands they have iDeal. In Belgium Bancontact. Dankort in Denmark. The list goes on [1]. Credit cards are not that common in Europe and not everyone has one. To appeal to a wider audience, one must support local payment methods. This is just one example of where things get more complicated compared to doing business in the US.
This is true. The banking infrastructure within the European Union is really good compared to the US.
The example I gave was regarding accepting online payments as a business from inviduals and other businesses. For US busineses, accepting credit cards is usually enough. Large bills can be paid by wire transfer. In the EU, accepting online payments is not that straightforward. Just figuring out the right VAT rate is complicated to begin with.
It is true that there is a lot of diversity in local payment methods, but you can easily cover most of your potential customers by simply offering credit/debit card, bank transfer and paypal options. It's more than enough to get you started.
As for the supposed insane amount of regulation, the majority of international trade is regulated at the EU level so it's quite unified. Not to mention e-commerce which is completely regulated by the EU.
I am not saying that there is not a considerable amount of particularity that may be hindering small startups in fast expansion across Europe but I would find it quite hard to believe that it is much of a factor for the likes of Apple and Amazon.
For example, we don't have a unified banking system in the EU. Each country has its own preferred method of payment. In the Netherlands they have iDeal. In Belgium Bancontact. Dankort in Denmark. The list goes on [1]. Credit cards are not that common in Europe and not everyone has one. To appeal to a wider audience, one must support local payment methods. This is just one example of where things get more complicated compared to doing business in the US.
[1] select the "Europe" tab: https://www.adyen.com/payment-methods