Here are the top five words (in their lemma, or dictionary form) for each part-of-speech, along with counts.

Nouns

time	507
ship	478
thing	288
question	247
light	245

Verbs

’s	1,536
have	1,383
say	1,014
get	650
do	623

Adjectives

good	333
other	228
little	214
same	195
more	194

Pronouns

I	7,515
it	3,237
my	1,490
you	1,208
they	1,199

Numerals

one	524
two	288
three	172
four	78
twenty	70

Coordinating Conjunctions

and	3,035
but	1,211
or	339
plus	28
either	16

Subordinating Conjunctions

if	454
how	405
when	268
why	250
as	203

Prepositions

of	2,784
in	1,725
to	1,477
on	1,121
for	901

Adverbs

just	684
so	448
now	385
back	339
then	327

Auxiliaries

be	4,215
do	969
can	753
would	386
will	382

Proper Nouns

Rocky	472
Astrophage	452
Earth	250
Stratt	238
Taumoeba	181

Determiners

the	8,105
a	3,762
an	431
no	382
that	356

Particles

to	2,525
not	1,952
’s	441

Interjections

yes	266
okay	176
no	143
yeah	139
oh	95