And -- The Greek word translated as "and" is used as the conjunction "and," but it also is used to add emphasis ("also").

it -- This is from the third-person, singular form of the verb.

came to pass -- The word translated as "came to pass" means "to become," that is, to enter into a new state. In Greek, especially as used by Jesus, it is the opposite of "being," which is existence in the current state. When applied to events, this word means "to happen," "to occur," or "take place." For things, it can be "to be produced." When the participle takes a predicate, the sense is "coming into" something.

as -- The word translated as "as" means "in," "within," "with" (an instrument), "by" (near), "by" (means of), "during" (time),  or "among"  with a dative object as the one here. The sense here is "during" the period of the sowing."

he  - (WW) -- The word translated as "he" is the Greek definite article; without a noun, it has the sense of "the one." The Greek article is much closer to our demonstrative pronouns ("this," "that," "these," "those") than the English "the." See this article for more.  This makes the following infinitive into a noun.

sowed,  - (WF) -- The Greek word translated as "sowed" means specifically to "sow seeds" and "to scatter" as in sowing seeds. It is, however, from the same root word as the Greek word for "seeds" so "seeding" is closer to its meaning. However, the verb form is not an active verb. It is an infinitive, preceded by an article. In Greek, this makes the verb into a noun describing its action,like an article with the gerund in English, "the sowing." The phrase is "during the seeding," which is translated as "as he sowed." However, this form is important here because the following singular verbs refer to this verbal noun, not the plural seeds. 

some -- (WN) -- The word translated as "who" is a demonstrative pronoun ("this" "that"), but it often acts as a pronoun, "he," "she," "it," "which," "what," "who," "whosoever," "where," "for which reason," and many similar meanings. This is a singular pronoun, "it" referring to "that sowing."

missing "on one hand" -- The untranslated word here is a particle, which. when used alone. expresses certainty, "truly" and "certainly." Alone in a question, it assumes the answer like "I take it" or "isn't it."  However, when used with the conjunction translated in later verses as "but" takes on the meaning "on one hand..." with the "on the other hand" identified by the "but" phrase. This "but" is in the following verses.

fell -- "Fell" is translated from a Greek word that means "to fall" and "to fall down." It is the root word for dozens of Greek terms involving moving from a higher state to a lower one. Like our word "to fall" it has a number of special meanings including "to fall into a given class", "to prostrate", "to fall from power", "to perish," and so on. The word translated as "fell" also means "failed."  Specifically, it means to "fall short."This verb is singular, "it fell." . The tense indicates it happening at a specific time in the past, present, or future. This is typical for a story.

by -- The Greek preposition translated as "by" has many meanings, many of which depend on the case of its object. With the accusative, its has a number of specialized meanings depending on the character of the verb, with coming/going "near," "beside," with placing "side-by-side," as a metaphor, "like" or "as a parody of, of comparison, "compared with" and many more.

the -- The word translated as "the" is the Greek definite article; without a noun, it has the sense of "the one." The Greek article is much closer to our demonstrative pronouns ("this," "that," "these," "those") than the English "the." See this article for more. 

way side, -- "Way side" is from a word meaning "way" or "road" but which is used symbolically to mean "a way of doing things" or "a philosophy of life." In Acts, followers of Jesus are described as those "belonging to the way."

and -- The Greek word translated as "and" is used as the conjunction "and," but it also is used to add emphasis ("also").

the -- The word translated as "the" is the Greek definite article; without a noun, it has the sense of "the one." The Greek article is much closer to our demonstrative pronouns ("this," "that," "these," "those") than the English "the." See this article for more. 

fowls - The sense with the previous article is "the winged ones."  Jesus always uses this word for bird, but it is a conscious choice here not to use the Greek word for birds or its diminutive, both of which are common.  All the English scientific words referring to birds come from common Greek forms, not this unusual one.

of the air   -- (OS) There is nothing in the Greek that can be translated as "of the air " in the source we use today but it does exist in the source that the KJV translators used. The Greek actually says "of the sky" using the word "sky" that is usually translated as "heaven."

came -- The word translated as "came" primarily means "to start out" but Christ usually uses it to mean "come" but not always. It indicates movement, especially its beginning, without indicating a direction toward or away from anything, so it works either as "start," "come," or "go," but it is more like our phrase "being underway." Our English word "show up" captures both the "start" and "come" ideas. See this article for more. This verb is singular because the plural "birds" is a neuter noun, so treated as a single group. This word indicates movement, especially its beginning, without indicating a direction toward or away from anything, so it works either as "come" or "go," but it is more like our phrase "being underway." Our English word "show up" captures both the "start" and "come" ideas. 

and -- The Greek word translated as "and" is used as the conjunction "and," but it also is used to add emphasis ("also"). 

devoured -  "Devoured" is from a verb that means "to eat up" and "to devour."  It is a term applied to animals of prey. It also means "to corrode" or "to be gnawed."  This verb to is singular though not matching "the birds," which seems to be the subject.This verb to is singular though "the birds" seems to be the subject.

it -- The word translated as "it" is the Greek word commonly translated as third-person pronouns in English.  Here it is neuter in the form of a subject or object of a verb or preposition.  This word, referring to the sowing, is again singular.

up. -- (CW) This is from the prefix of the previous verb that means "down." In English, we say "ate up" more than "ate down" but both have different meanings. Using "devout" instead of "ate" further confuses things.