diff --git a/analyzer/block.go b/analyzer/block.go
index 4ad34e1..1ecd154 100644
--- a/analyzer/block.go
+++ b/analyzer/block.go
@@ -4,7 +4,6 @@ import "git.tebibyte.media/arf/arf/parser"
 
 // Block represents a scoped block of phrases.
 type Block struct {
-	locatable
 	phrases []Phrase
 
 	// TODO: create a scope struct and embed it
@@ -31,7 +30,10 @@ func (analyzer *analysisOperation) analyzeBlock (
 	err error,
 ) {
 	for _, inputPhrase := range inputBlock {
-		
+		var outputPhrase Phrase
+		outputPhrase, err = analyzer.analyzePhrase(inputPhrase)
+		block.phrases = append(block.phrases, outputPhrase)
 	}
+	
 	return
 }
diff --git a/analyzer/phrase.go b/analyzer/phrase.go
index 1f72db9..864bd34 100644
--- a/analyzer/phrase.go
+++ b/analyzer/phrase.go
@@ -1,9 +1,12 @@
 package analyzer
 
+import "regexp"
 import "git.tebibyte.media/arf/arf/file"
 import "git.tebibyte.media/arf/arf/parser"
 import "git.tebibyte.media/arf/arf/infoerr"
 
+var validNameRegex = regexp.MustCompile("^[a-zA-Z_][a-zA-Z0-9_]*$")
+
 type Phrase interface {
 	// Provided by phraseBase
 	Location () (location file.Location)
@@ -19,6 +22,17 @@ type ArbitraryPhrase struct {
 	arguments []Argument
 }
 
+func (phrase ArbitraryPhrase) ToString (indent int) (output string) {
+	output += doIndent(indent, "phrase\n")
+	output += doIndent(indent + 1, phrase.command, "\n")
+
+	for _, argument := range phrase.arguments {
+		output += argument.ToString(indent + 1)
+	}
+
+	return
+}
+
 type CastPhrase struct {
 	phraseBase
 	command Argument
@@ -33,5 +47,41 @@ func (analyzer *analysisOperation) analyzePhrase (
 	phrase Phrase,
 	err error,
 ) {
+	base := phraseBase {
+		
+	}
+
+	arguments := []Argument { }
+	for index := 0; index < inputPhrase.Length(); index ++ {
+		inputArgument := inputPhrase.Argument(index)
+		
+		var argument Argument
+		argument, err = analyzer.analyzeArgument(inputArgument)
+		if err != nil { return }
+		arguments = append(arguments, argument)
+	}
+
+	switch inputPhrase.Kind() {
+	case parser.PhraseKindArbitrary:
+		command := inputPhrase.Command().Value().(string)
+		if !validNameRegex.Match([]byte(command)) {
+			err = inputPhrase.NewError (
+				"command cannot contain characters other " +
+				"than a-z, A-Z, 0-9, underscores, or begin " +
+				"with a number",
+				infoerr.ErrorKindError)
+			return
+		}
+
+		outputPhrase := ArbitraryPhrase {
+			phraseBase: base,
+			command:    command,
+			arguments:  arguments,
+		}
+		phrase = outputPhrase
+		
+	default:
+		panic("phrase kind not implemented")
+	}
 	return
 }
diff --git a/parser/tree.go b/parser/tree.go
index a41bc53..bb3a5a2 100644
--- a/parser/tree.go
+++ b/parser/tree.go
@@ -277,7 +277,7 @@ const (
 // Phrase represents a function call or operator. In ARF they are the same
 // syntactical concept.
 type Phrase struct {
-	location  file.Location
+	locatable
 	returnees []Argument
 	multiValuable