diff --git a/Makefile b/Makefile
index 28b21a6..050d3f0 100644
--- a/Makefile
+++ b/Makefile
@@ -1,6 +1,7 @@
 .PHONY: lint test coverage
 
 lint:
+	golangci-lint fmt
 	golangci-lint run ./...
 
 test:
diff --git a/README.md b/README.md
index e2b198a..c3c204e 100644
--- a/README.md
+++ b/README.md
@@ -28,7 +28,7 @@ Search:
 
 ```bash
 goplaces search "coffee" --min-rating 4 --open-now --limit 5 \
-  --lat 40.8065 --lng -73.9719 --radius-m 3000
+  --lat 40.8065 --lng -73.9719 --radius-m 3000 --language en --region US
 ```
 
 Details:
@@ -88,6 +88,8 @@ resp, err := client.Search(ctx, goplaces.SearchRequest{
 - `Filters.Types` maps to `includedType` (Google supports a single value). Only the first type is sent.
 - Price levels map to Google enums: `0` (free) → `4` (very expensive).
 - Use `GOOGLE_PLACES_BASE_URL` to override the endpoint (useful for tests).
+- Field masks are defined in `client.go` constants; extend them if you need more fields.
+- Google Places API usage is billed and quota-limited; keep an eye on your Cloud Console quotas.
 
 ## Testing
 
diff --git a/client.go b/client.go
index a883abf..9fb1246 100644
--- a/client.go
+++ b/client.go
@@ -9,6 +9,7 @@ import (
 	"fmt"
 	"io"
 	"net/http"
+	"net/url"
 	"strings"
 	"time"
 )
@@ -99,7 +100,11 @@ func (c *Client) Search(ctx context.Context, req SearchRequest) (SearchResponse,
 	}
 
 	body := buildSearchBody(req)
-	payload, err := c.doRequest(ctx, http.MethodPost, "/places:searchText", body, searchFieldMask)
+	endpoint, err := c.buildURL("/places:searchText", nil)
+	if err != nil {
+		return SearchResponse{}, err
+	}
+	payload, err := c.doRequest(ctx, http.MethodPost, endpoint, body, searchFieldMask)
 	if err != nil {
 		return SearchResponse{}, err
 	}
@@ -122,13 +127,25 @@ func (c *Client) Search(ctx context.Context, req SearchRequest) (SearchResponse,
 
 // Details fetches details for a specific place ID.
 func (c *Client) Details(ctx context.Context, placeID string) (PlaceDetails, error) {
-	placeID = strings.TrimSpace(placeID)
+	return c.DetailsWithOptions(ctx, DetailsRequest{PlaceID: placeID})
+}
+
+// DetailsWithOptions fetches place details with locale hints.
+func (c *Client) DetailsWithOptions(ctx context.Context, req DetailsRequest) (PlaceDetails, error) {
+	placeID := strings.TrimSpace(req.PlaceID)
 	if placeID == "" {
 		return PlaceDetails{}, ValidationError{Field: "place_id", Message: "required"}
 	}
 
-	path := "/places/" + placeID
-	payload, err := c.doRequest(ctx, http.MethodGet, path, nil, detailsFieldMask)
+	endpoint, err := c.buildURL("/places/"+placeID, map[string]string{
+		"languageCode": strings.TrimSpace(req.Language),
+		"regionCode":   strings.TrimSpace(req.Region),
+	})
+	if err != nil {
+		return PlaceDetails{}, err
+	}
+
+	payload, err := c.doRequest(ctx, http.MethodGet, endpoint, nil, detailsFieldMask)
 	if err != nil {
 		return PlaceDetails{}, err
 	}
@@ -152,8 +169,18 @@ func (c *Client) Resolve(ctx context.Context, req LocationResolveRequest) (Locat
 		"textQuery": req.LocationText,
 		"pageSize":  req.Limit,
 	}
+	if strings.TrimSpace(req.Language) != "" {
+		body["languageCode"] = strings.TrimSpace(req.Language)
+	}
+	if strings.TrimSpace(req.Region) != "" {
+		body["regionCode"] = strings.TrimSpace(req.Region)
+	}
 
-	payload, err := c.doRequest(ctx, http.MethodPost, "/places:searchText", body, resolveFieldMask)
+	endpoint, err := c.buildURL("/places:searchText", nil)
+	if err != nil {
+		return LocationResolveResponse{}, err
+	}
+	payload, err := c.doRequest(ctx, http.MethodPost, endpoint, body, resolveFieldMask)
 	if err != nil {
 		return LocationResolveResponse{}, err
 	}
@@ -174,7 +201,7 @@ func (c *Client) Resolve(ctx context.Context, req LocationResolveRequest) (Locat
 func (c *Client) doRequest(
 	ctx context.Context,
 	method string,
-	path string,
+	endpoint string,
 	body any,
 	fieldMask string,
 ) ([]byte, error) {
@@ -182,7 +209,6 @@ func (c *Client) doRequest(
 		return nil, ErrMissingAPIKey
 	}
 
-	url := c.baseURL + path
 	var reader io.Reader
 	if body != nil {
 		payload, err := json.Marshal(body)
@@ -192,7 +218,7 @@ func (c *Client) doRequest(
 		reader = bytes.NewReader(payload)
 	}
 
-	request, err := http.NewRequestWithContext(ctx, method, url, reader)
+	request, err := http.NewRequestWithContext(ctx, method, endpoint, reader)
 	if err != nil {
 		return nil, fmt.Errorf("goplaces: build request: %w", err)
 	}
@@ -226,6 +252,28 @@ func (c *Client) doRequest(
 	return payload, nil
 }
 
+func (c *Client) buildURL(path string, query map[string]string) (string, error) {
+	endpoint := c.baseURL + path
+	if len(query) == 0 {
+		return endpoint, nil
+	}
+
+	parsed, err := url.Parse(endpoint)
+	if err != nil {
+		return "", fmt.Errorf("goplaces: invalid url: %w", err)
+	}
+
+	values := parsed.Query()
+	for key, value := range query {
+		if strings.TrimSpace(value) == "" {
+			continue
+		}
+		values.Set(key, value)
+	}
+	parsed.RawQuery = values.Encode()
+	return parsed.String(), nil
+}
+
 func buildSearchBody(req SearchRequest) map[string]any {
 	textQuery := req.Query
 	if req.Filters != nil && strings.TrimSpace(req.Filters.Keyword) != "" {
@@ -236,6 +284,12 @@ func buildSearchBody(req SearchRequest) map[string]any {
 		"textQuery": textQuery,
 		"pageSize":  req.Limit,
 	}
+	if strings.TrimSpace(req.Language) != "" {
+		body["languageCode"] = strings.TrimSpace(req.Language)
+	}
+	if strings.TrimSpace(req.Region) != "" {
+		body["regionCode"] = strings.TrimSpace(req.Region)
+	}
 
 	if req.PageToken != "" {
 		body["pageToken"] = req.PageToken
diff --git a/client_test.go b/client_test.go
index 408b291..1ba4e52 100644
--- a/client_test.go
+++ b/client_test.go
@@ -65,6 +65,8 @@ func TestSearchSuccess(t *testing.T) {
 		Query:     "coffee",
 		Limit:     5,
 		PageToken: "token",
+		Language:  "en",
+		Region:    "US",
 		Filters: &Filters{
 			Keyword:     "best",
 			Types:       []string{"cafe"},
@@ -108,6 +110,12 @@ func TestSearchSuccess(t *testing.T) {
 	if gotRequest["pageToken"] != "token" {
 		t.Fatalf("unexpected pageToken: %#v", gotRequest["pageToken"])
 	}
+	if gotRequest["languageCode"] != "en" {
+		t.Fatalf("unexpected languageCode: %#v", gotRequest["languageCode"])
+	}
+	if gotRequest["regionCode"] != "US" {
+		t.Fatalf("unexpected regionCode: %#v", gotRequest["regionCode"])
+	}
 }
 
 func TestSearchHTTPError(t *testing.T) {
@@ -146,6 +154,12 @@ func TestDetailsSuccess(t *testing.T) {
 		if r.URL.Path != "/v1/places/place-123" {
 			t.Fatalf("unexpected path: %s", r.URL.Path)
 		}
+		if r.URL.Query().Get("languageCode") != "en" {
+			t.Fatalf("unexpected languageCode: %s", r.URL.Query().Get("languageCode"))
+		}
+		if r.URL.Query().Get("regionCode") != "US" {
+			t.Fatalf("unexpected regionCode: %s", r.URL.Query().Get("regionCode"))
+		}
 		if r.Header.Get("X-Goog-FieldMask") != detailsFieldMask {
 			t.Fatalf("unexpected field mask: %s", r.Header.Get("X-Goog-FieldMask"))
 		}
@@ -166,7 +180,11 @@ func TestDetailsSuccess(t *testing.T) {
 	defer server.Close()
 
 	client := NewClient(Options{APIKey: "test-key", BaseURL: server.URL + "/v1"})
-	place, err := client.Details(context.Background(), "place-123")
+	place, err := client.DetailsWithOptions(context.Background(), DetailsRequest{
+		PlaceID:  "place-123",
+		Language: "en",
+		Region:   "US",
+	})
 	if err != nil {
 		t.Fatalf("details error: %v", err)
 	}
@@ -182,10 +200,18 @@ func TestDetailsSuccess(t *testing.T) {
 }
 
 func TestResolveSuccess(t *testing.T) {
+	var gotRequest map[string]any
 	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		if r.Header.Get("X-Goog-FieldMask") != resolveFieldMask {
 			t.Fatalf("unexpected field mask: %s", r.Header.Get("X-Goog-FieldMask"))
 		}
+		body, err := io.ReadAll(r.Body)
+		if err != nil {
+			t.Fatalf("read body: %v", err)
+		}
+		if err := json.Unmarshal(body, &gotRequest); err != nil {
+			t.Fatalf("decode body: %v", err)
+		}
 		_, _ = w.Write([]byte(`{
   "places": [
     {
@@ -201,13 +227,23 @@ func TestResolveSuccess(t *testing.T) {
 	defer server.Close()
 
 	client := NewClient(Options{APIKey: "test-key", BaseURL: server.URL})
-	response, err := client.Resolve(context.Background(), LocationResolveRequest{LocationText: "Downtown"})
+	response, err := client.Resolve(context.Background(), LocationResolveRequest{
+		LocationText: "Downtown",
+		Language:     "en",
+		Region:       "US",
+	})
 	if err != nil {
 		t.Fatalf("resolve error: %v", err)
 	}
 	if len(response.Results) != 1 {
 		t.Fatalf("expected 1 result")
 	}
+	if gotRequest["languageCode"] != "en" {
+		t.Fatalf("unexpected languageCode: %#v", gotRequest["languageCode"])
+	}
+	if gotRequest["regionCode"] != "US" {
+		t.Fatalf("unexpected regionCode: %#v", gotRequest["regionCode"])
+	}
 }
 
 func TestMissingAPIKey(t *testing.T) {
diff --git a/internal/cli/cli_test.go b/internal/cli/cli_test.go
index df22795..d020af2 100644
--- a/internal/cli/cli_test.go
+++ b/internal/cli/cli_test.go
@@ -2,6 +2,7 @@ package cli
 
 import (
 	"bytes"
+	"encoding/json"
 	"errors"
 	"net/http"
 	"net/http/httptest"
@@ -32,7 +33,7 @@ func TestRunSearchJSON(t *testing.T) {
 	}, &stdout, &stderr)
 
 	if exitCode != 0 {
-		t.Fatalf("expected exit code 0, got %d", exitCode)
+		t.Fatalf("expected exit code 0, got %d (stdout=%s stderr=%s)", exitCode, stdout.String(), stderr.String())
 	}
 	if stderr.Len() != 0 {
 		t.Fatalf("unexpected stderr: %s", stderr.String())
@@ -59,13 +60,64 @@ func TestRunSearchHuman(t *testing.T) {
 	}, &stdout, &stderr)
 
 	if exitCode != 0 {
-		t.Fatalf("expected exit code 0, got %d", exitCode)
+		t.Fatalf("expected exit code 0, got %d (stdout=%s stderr=%s)", exitCode, stdout.String(), stderr.String())
 	}
 	if !strings.Contains(stdout.String(), "Cafe") {
 		t.Fatalf("unexpected stdout: %s", stdout.String())
 	}
 }
 
+func TestRunSearchWithFilters(t *testing.T) {
+	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		var payload map[string]any
+		if err := json.NewDecoder(r.Body).Decode(&payload); err != nil {
+			t.Fatalf("decode request: %v", err)
+		}
+		if payload["includedType"] != "cafe" {
+			t.Fatalf("unexpected includedType: %#v", payload["includedType"])
+		}
+		if payload["languageCode"] != "en" {
+			t.Fatalf("unexpected languageCode: %#v", payload["languageCode"])
+		}
+		if payload["regionCode"] != "US" {
+			t.Fatalf("unexpected regionCode: %#v", payload["regionCode"])
+		}
+		_, _ = w.Write([]byte(`{"places": [{"id": "abc"}]}`))
+	}))
+	defer server.Close()
+
+	var stdout bytes.Buffer
+	var stderr bytes.Buffer
+
+	exitCode := Run([]string{
+		"search",
+		"coffee",
+		"--api-key", "test-key",
+		"--base-url", server.URL,
+		"--json",
+		"--keyword", "best",
+		"--type", "cafe",
+		"--open-now=true",
+		"--min-rating", "4.2",
+		"--price-level", "1",
+		"--lat", "40.0",
+		"--lng=-70.0",
+		"--radius-m", "500",
+		"--language", "en",
+		"--region", "US",
+	}, &stdout, &stderr)
+
+	if exitCode != 0 {
+		t.Fatalf("expected exit code 0, got %d (stdout=%s stderr=%s)", exitCode, stdout.String(), stderr.String())
+	}
+	if stderr.Len() != 0 {
+		t.Fatalf("unexpected stderr: %s", stderr.String())
+	}
+	if !strings.Contains(stdout.String(), "\"results\"") {
+		t.Fatalf("unexpected stdout: %s", stdout.String())
+	}
+}
+
 func TestRunDetailsJSON(t *testing.T) {
 	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		if r.URL.Path != "/places/place-1" {
diff --git a/internal/cli/root.go b/internal/cli/root.go
index 7b0f43c..e51d0ea 100644
--- a/internal/cli/root.go
+++ b/internal/cli/root.go
@@ -28,6 +28,8 @@ type SearchCmd struct {
 	Query      string   `arg:"" name:"query" help:"Search text."`
 	Limit      int      `help:"Max results (1-20)." default:"10"`
 	PageToken  string   `help:"Page token for pagination."`
+	Language   string   `help:"BCP-47 language code (e.g. en, en-US)."`
+	Region     string   `help:"CLDR region code (e.g. US, DE)."`
 	Keyword    string   `help:"Keyword to append to the query."`
 	Type       []string `help:"Place type filter (includedType). Repeatable."`
 	OpenNow    *bool    `help:"Return only currently open places."`
@@ -40,11 +42,15 @@ type SearchCmd struct {
 
 // DetailsCmd fetches place details.
 type DetailsCmd struct {
-	PlaceID string `arg:"" name:"place_id" help:"Place ID."`
+	PlaceID  string `arg:"" name:"place_id" help:"Place ID."`
+	Language string `help:"BCP-47 language code (e.g. en, en-US)."`
+	Region   string `help:"CLDR region code (e.g. US, DE)."`
 }
 
 // ResolveCmd resolves a location string into candidates.
 type ResolveCmd struct {
 	LocationText string `arg:"" name:"location" help:"Location text to resolve."`
 	Limit        int    `help:"Max results (1-10)." default:"5"`
+	Language     string `help:"BCP-47 language code (e.g. en, en-US)."`
+	Region       string `help:"CLDR region code (e.g. US, DE)."`
 }
diff --git a/internal/cli/run.go b/internal/cli/run.go
index 52fdb28..5e0a2a5 100644
--- a/internal/cli/run.go
+++ b/internal/cli/run.go
@@ -118,6 +118,8 @@ func (c *SearchCmd) Run(app *App) error {
 		Query:     c.Query,
 		Limit:     c.Limit,
 		PageToken: c.PageToken,
+		Language:  c.Language,
+		Region:    c.Region,
 	}
 
 	filters := goplaces.Filters{}
@@ -172,7 +174,11 @@ func (c *SearchCmd) Run(app *App) error {
 
 // Run executes the details command.
 func (c *DetailsCmd) Run(app *App) error {
-	response, err := app.client.Details(context.Background(), c.PlaceID)
+	response, err := app.client.DetailsWithOptions(context.Background(), goplaces.DetailsRequest{
+		PlaceID:  c.PlaceID,
+		Language: c.Language,
+		Region:   c.Region,
+	})
 	if err != nil {
 		return err
 	}
@@ -190,6 +196,8 @@ func (c *ResolveCmd) Run(app *App) error {
 	request := goplaces.LocationResolveRequest{
 		LocationText: c.LocationText,
 		Limit:        c.Limit,
+		Language:     c.Language,
+		Region:       c.Region,
 	}
 
 	response, err := app.client.Resolve(context.Background(), request)
diff --git a/types.go b/types.go
index 1531138..e84124f 100644
--- a/types.go
+++ b/types.go
@@ -7,6 +7,8 @@ type SearchRequest struct {
 	LocationBias *LocationBias `json:"location_bias,omitempty"`
 	Limit        int           `json:"limit,omitempty"`
 	PageToken    string        `json:"page_token,omitempty"`
+	Language     string        `json:"language,omitempty"`
+	Region       string        `json:"region,omitempty"`
 }
 
 // Filters are optional search refinements.
@@ -68,6 +70,15 @@ type PlaceDetails struct {
 type LocationResolveRequest struct {
 	LocationText string `json:"location_text"`
 	Limit        int    `json:"limit,omitempty"`
+	Language     string `json:"language,omitempty"`
+	Region       string `json:"region,omitempty"`
+}
+
+// DetailsRequest fetches place details with optional locale hints.
+type DetailsRequest struct {
+	PlaceID  string `json:"place_id"`
+	Language string `json:"language,omitempty"`
+	Region   string `json:"region,omitempty"`
 }
 
 // LocationResolveResponse contains resolved locations.