Which are or were the most confusing words you had to learn in a foreign language?

For me, those were in English: tough, though, thought, through, thorough, and throughout. So confusing!

Which are yours?

(taken from here)

<Shī Shì Shí Shī Shǐ>

“Shí Shì Shī Shì Shī Shì, Shì Shī, Shì Shí Shí Shī.Shì Shí Shí Shì Shì Shì Shī. Shí Shí, Shì Shí Shī Shì Shì. Shì Shí, Shì Shī Shì Shì Shì. Shì Shì Shì Shí Shī, Shì Shǐ Shì, Shǐ Shì Shí Shī Shì Shì. Shì Shí Shì Shí Shī Shī, Shì Shí Shì. Shí Shì Shī, Shì Shǐ Shì Shì Shí Shì. Shí Shì Shì, Shì Shǐ Shì Shí Shì Shí Shī. Shí Shí, Shǐ Shí Shì Shí Shī, Shí Shí Shí Shī Shī. Shì Shì Shì Shì.”

It's a romanized Chinese story. That's why one needs to learn good tones. The Chinese text looks much better imo:

<施氏食獅史>

“石室詩士施氏，嗜獅，誓食十獅。施氏時時適市視獅。十時，適十獅適市。是時，適施氏適市。氏視是十獅，恃矢勢，使是十獅逝世。氏拾是十獅屍，適石室。石室濕，氏使侍拭石室。石室拭，氏始試食是十獅。食時，始識是十獅，實十石獅屍。試釋是事。”

English:

<The story of Mr.Shi eating lions>

“There was a poet named Mr.Shi who lives in a stone den. He liked to eat lions, and vowed to eat ten lions. Therefore Mr. Shi would usually visit the market to look for lions. At 10 o’clock exactly ten lions just arrived at the market. At that very moment, Mr.Shi shot a few arrows from his bow and killed those ten lions. Mr. Shi then brought the ten dead lions back to his stone den. Because the den might be too wet to store the lions. So he ordered his servant to clean and dry the den. After the den was cleaned, Mr.Shi started to try to eat those ten lions. However, only until he was eating the lions he found out that those ten dead lions were actually ten stone lions. Would you try to explain what was happening?”

To be honest, I'm still confused on some English prepositions: IN, ON, AT  

leosmith wrote:

(taken from here)

<Shī Shì Shí Shī Shǐ>

“Shí Shì Shī Shì Shī Shì, Shì Shī, Shì Shí Shí Shī.Shì Shí Shí Shì Shì Shì Shī. Shí Shí, Shì Shí Shī Shì Shì. Shì Shí, Shì Shī Shì Shì Shì. Shì Shì Shì Shí Shī, Shì Shǐ Shì, Shǐ Shì Shí Shī Shì Shì. Shì Shí Shì Shí Shī Shī, Shì Shí Shì. Shí Shì Shī, Shì Shǐ Shì Shì Shí Shì. Shí Shì Shì, Shì Shǐ Shì Shí Shì Shí Shī. Shí Shí, Shǐ Shí Shì Shí Shī, Shí Shí Shí Shī Shī. Shì Shì Shì Shì.”

It's a romanized Chinese story. That's why one needs to learn good tones. The Chinese text looks much better imo:

<施氏食獅史>

“石室詩士施氏，嗜獅，誓食十獅。施氏時時適市視獅。十時，適十獅適市。是時，適施氏適市。氏視是十獅，恃矢勢，使是十獅逝世。氏拾是十獅屍，適石室。石室濕，氏使侍拭石室。石室拭，氏始試食是十獅。食時，始識是十獅，實十石獅屍。試釋是事。”

English:

<The story of Mr.Shi eating lions>

“There was a poet named Mr.Shi who lives in a stone den. He liked to eat lions, and vowed to eat ten lions. Therefore Mr. Shi would usually visit the market to look for lions. At 10 o’clock exactly ten lions just arrived at the market. At that very moment, Mr.Shi shot a few arrows from his bow and killed those ten lions. Mr. Shi then brought the ten dead lions back to his stone den. Because the den might be too wet to store the lions. So he ordered his servant to clean and dry the den. After the den was cleaned, Mr.Shi started to try to eat those ten lions. However, only until he was eating the lions he found out that those ten dead lions were actually ten stone lions. Would you try to explain what was happening?”

That just freaked me out!

leosmith wrote:

(taken from here)
<Shī Shì Shí Shī Shǐ>
“Shí Shì Shī Shì Shī Shì, Shì Shī, Shì Shí Shí Shī.Shì Shí Shí Shì Shì Shì Shī. Shí Shí, Shì Shí Shī Shì Shì. Shì Shí, Shì Shī Shì Shì Shì. Shì Shì Shì Shí Shī, Shì Shǐ Shì, Shǐ Shì Shí Shī Shì Shì. Shì Shí Shì Shí Shī Shī, Shì Shí Shì. Shí Shì Shī, Shì Shǐ Shì Shì Shí Shì. Shí Shì Shì, Shì Shǐ Shì Shí Shì Shí Shī. Shí Shí, Shǐ Shí Shì Shí Shī, Shí Shí Shí Shī Shī. Shì Shì Shì Shì.”
It's a romanized Chinese story. That's why one needs to learn good tones. The Chinese text looks much better imo:
<施氏食獅史>
“石室詩士施氏，嗜獅，誓食十獅。施氏時時適市視獅。十時，適十獅適市。是時，適施氏適市。氏視是十獅，恃矢勢，使是十獅逝世。氏拾是十獅屍，適石室。石室濕，氏使侍拭石室。石室拭，氏始試食是十獅。食時，始識是十獅，實十石獅屍。試釋是事。”
English:
<The story of Mr.Shi eating lions>
“There was a poet named Mr.Shi who lives in a stone den. He liked to eat lions, and vowed to eat ten lions. Therefore Mr. Shi would usually visit the market to look for lions. At 10 o’clock exactly ten lions just arrived at the market. At that very moment, Mr.Shi shot a few arrows from his bow and killed those ten lions. Mr. Shi then brought the ten dead lions back to his stone den. Because the den might be too wet to store the lions. So he ordered his servant to clean and dry the den. After the den was cleaned, Mr.Shi started to try to eat those ten lions. However, only until he was eating the lions he found out that those ten dead lions were actually ten stone lions. Would you try to explain what was happening?”

Oh what a tongue twister of a story! Amazingly it only uses 3 letters. I don't know if I should feel discouraged or challenged.