fix(all): correct minor typos (#635)

diff --git a/internal/gensupport/media.go b/internal/gensupport/media.go
index 0288cc3..0460ab5 100644
--- a/internal/gensupport/media.go
+++ b/internal/gensupport/media.go
@@ -55,7 +55,7 @@
 	return cs.r.Read(p)
 }
 
-// ContentType returns the sniffed content type, and whether the content type was succesfully sniffed.
+// ContentType returns the sniffed content type, and whether the content type was successfully sniffed.
 func (cs *contentSniffer) ContentType() (string, bool) {
 	if cs.sniffed {
 		return cs.ctype, cs.ctype != ""
@@ -88,7 +88,7 @@
 		return media, ctype
 	}
 
-	// For backwards compatability, allow clients to set content
+	// For backwards compatibility, allow clients to set content
 	// type by providing a ContentTyper for media.
 	if typer, ok := media.(googleapi.ContentTyper); ok {
 		return media, typer.ContentType()
diff --git a/option/internaloption/internaloption.go b/option/internaloption/internaloption.go
index d5debb7..b4d78a8 100644
--- a/option/internaloption/internaloption.go
+++ b/option/internaloption/internaloption.go
@@ -20,7 +20,7 @@
 //
 // It should only be used internally by generated clients.
 //
-// This is similar to WithEndpoint, but allows us to determine whether the user has overriden the default endpoint.
+// This is similar to WithEndpoint, but allows us to determine whether the user has overridden the default endpoint.
 func WithDefaultEndpoint(url string) option.ClientOption {
 	return defaultEndpointOption(url)
 }
diff --git a/transport/bytestream/client_test.go b/transport/bytestream/client_test.go
index e21d811..79ecc7f 100644
--- a/transport/bytestream/client_test.go
+++ b/transport/bytestream/client_test.go
@@ -245,7 +245,7 @@
 	setup.Close()
 	_, err := setup.client.NewWriter(setup.ctx, "should fail")
 	if err == nil {
-		t.Fatalf("NewWriter(%q): err=%v", "shoudl fail", err)
+		t.Fatalf("NewWriter(%q): err=%v", "should fail", err)
 	}
 }
 
diff --git a/transport/grpc/pool.go b/transport/grpc/pool.go
index 32c0293..4cf94a2 100644
--- a/transport/grpc/pool.go
+++ b/transport/grpc/pool.go
@@ -63,7 +63,7 @@
 	return p.Conn().NewStream(ctx, desc, method, opts...)
 }
 
-// multiError represents errors from mulitple conns in the group.
+// multiError represents errors from multiple conns in the group.
 //
 // TODO: figure out how and whether this is useful to export. End users should
 // not be depending on the transport/grpc package directly, so there might need