Hmm, I tried several things (which I included in the code below, in square brackets) and I don't know why this happens.

Perhaps if you included Graham Nelson's extension "Metric Units" or "Approximate Metric Units?"

If you simply ignore singulars and plurals, the code compiles, as in:

**Code:**

X is a room. Lady Gaga is a woman in X.

A height is a kind of value.

[1 foot (singular) specifies a height.

2 feet (plural) specifies a height.

1 inch (singular) specifies a height scaled down by 12.

2 inches (plural) specifies a height scaled down by 12.]

5 feet 11 inches specifies a height.

A person has a height.

The height of Lady Gaga is 5 feet 2 inches.

After examining Gaga, say "She is [the height of Lady Gaga] tall."

This gives:

**Quote:**

>x gaga

You see nothing special about Lady Gaga.

She is 5 feet 2 inches tall.

But if I write:

**Code:**

The height of Lady Gaga is 5 feet 1 inch.

this does not compile.

On the other hand, if I write:

**Code:**

5 feet 1 inch specifies a height.

The height of Lady Gaga is 5 feet 1 inch.

this compiles, but gives a totally weird result:

**Quote:**

>x gaga

You see nothing special about Lady Gaga.

She is 0 feet 11 inches tall

By the way, I am a bit of a noob, so...