I'm Australian and married to an American. When our kids visited the US they were surprised people couldn't understand their English.

• We live in Australia, but my wife is from Texas, so we visit her family regularly.
• We took our twin sons to the US for the first time when they were 11.
• They were amazed at the lack of healthy food options and the dollar bills all being the same color. 

The first time we took our twin sons to the US from Australia, they were surprised by how different things were between the two countries.

Almost immediately after arriving, while driving into downtown Los Angeles from the airport, they were surprised at the sheer number and variety of fast-food chains along the highway.

In Australia, we have several major fast-food chains, but our sons, Charlie and Thomas, couldn't believe how many different chains there were in the US. They were surprised that there was a need for dozens of different burger chains, fried chicken restaurants, and fast food joints. We let them pick one to try, and they chose the iconic In-N-Out.

They couldn't understand why all the dollar bills looked the same

Every Australian bill is a different color, making it easy to distinguish. Charlie and Thomas were surprised that every American dollar bill looked the same. This concerned them, as they were worried they would accidentally hand over a 20-dollar bill instead of a one-dollar one and lose money. I solved this by only giving them one-dollar bills.

They also had a problem with tax being added at the cash register which they weren't used to.

Determined to maximize their spending, they were frustrated by the pricing system. In Australia, the price displayed is the final price (including tax and tip), so they found it challenging to determine what an item would cost. We explained they needed to add tax (and occasionally a tip), but the differing state taxes necessitated using a calculator each time, which diminished their shopping experience.

Being asked to repeat themselves annoyed them

I don't believe our Aussie accents are very strong, but many Americans found it difficult to understand Charlie and Thomas and were often asked to repeat themselves. A few people even asked if they were speaking English.

Both hate tomatoes, so when ordering, they always ask for "no tomatoes." However, they pronounce it as "to-mah-to" rather than how Americans pronounce it, often leading to confusion. Another word that caused an issue was water, which we pronounce "war-ta."

By the end of the trip, they had learned to say tomatoes and water in an American accent.

The fast food novelty eventually wore out, leading to a surprising conversation

As we traveled across several states, we endeavored to eat healthy food but found this a challenge among the spate of cheap (but generally fried) fast food options. Midway through our second week of vacation, Charlie, who loves his junk food and is known for avoiding vegetables, shocked me. While choosing where to eat, he turned to my wife and me and said, "Can we please go somewhere with vegetables and where the food isn't fried." I was stunned.

Another thing that stood out to them was the patriotism of Americans

During our visit, they remarked on the number of houses and businesses that proudly displayed the American flag — it is rare to see an Australian flag outside an official place back home. We also attended a few sporting games, and they didn't expect the anthem to be sung — in Australia, we sing the anthem only before major events. Both boys enjoyed the spirit and passion the crowd had when singing the song and the respect shown to veterans.

My in-laws live in Texas, and the boys loved spending time in their backyard shooting BB guns at targets. They loved it so much that they requested BB guns for Christmas. Unfortunately, they are illegal in Australia, so their request had to be denied.

Since that first trip, Charlie and Thomas have been back several times, so there isn't much that surprises them anymore. Now that they are 17, they have stopped asking for a BB gun — instead, they ask for 100-dollar bills to spend. I guess they are no longer worried about the sameness of the bills.